Fact-checked by Grok 2 weeks ago

Cold wave

A cold wave is a rapid fall in temperature within a 24-hour period, followed by extreme low temperatures that persist for an extended duration, with thresholds varying by region and season but generally posing risks to life, property, agriculture, and infrastructure.^[1] These events typically arise from the southward advection of dense, cold air masses originating from polar regions, often triggered by disruptions to the stratospheric polar vortex, such as sudden stratospheric warmings that weaken its circulation and allow Arctic air to spill into mid-latitudes.^[2]^[3] Cold waves can occur in winter but also in other seasons if temperatures drop sharply below seasonal norms, and they are influenced by large-scale atmospheric patterns like Rossby waves, which facilitate the transport of cold air equatorward.^[4] The impacts of cold waves are multifaceted and severe, including heightened risks of hypothermia, frostbite, and exacerbated respiratory or cardiovascular conditions, particularly among vulnerable populations such as the elderly and homeless.^[5] Economically, they damage crops through freezing, disrupt transportation due to icy roads and snow, strain energy grids from increased heating demands, and cause infrastructure failures like burst pipes or power outages.^[1] Environmentally, cold waves can stress ecosystems by harming wildlife and altering seasonal patterns, while in a changing climate, their frequency and intensity in the northern midlatitudes have shown a trend toward mildness over recent decades, though individual events may still be extreme.^[6]

Definition and Characteristics

Definition

A cold wave is defined meteorologically as a rapid fall in temperature within a 24-hour period requiring substantially increased protection against the cold for agriculture, industry, commerce, and social activities. According to the U.S. National Weather Service, this includes extreme low temperatures or wind chill values that pose significant risks, with criteria varying by region to account for local norms.^[7]^[8] Unlike routine seasonal winter weather, cold waves represent abnormal and unusually severe cold spells that deviate markedly from expected norms for the time and location, analogous to heat waves but involving extreme low temperatures rather than highs. This abnormality is determined by the speed and magnitude of the temperature decline, emphasizing impacts beyond typical cold snaps.^[7] Key characteristics of cold waves include an extended duration, often exacerbated by high winds that intensify wind chill effects, as well as accompanying precipitation in the form of snow, sleet, or ice that amplifies hazards. These features collectively heighten risks to human health, infrastructure, and ecosystems by creating conditions more severe than isolated low temperatures.^[7] The term "cold wave" entered weather reporting in the late 19th century, with the U.S. Army Signal Service's Weather Bureau first issuing cold wave warnings and displaying associated signal flags as early as 1878 to alert the public to impending sharp temperature drops. This marked an early advancement in forecasting extreme weather events.^[9]

Regional Variations and Criteria

Cold wave criteria vary significantly by region to account for local climate norms, geography, and seasonal expectations, ensuring that warnings are relevant to the potential impacts on populations and infrastructure in diverse environments. These variations typically involve thresholds based on absolute temperatures, departures from historical averages, duration, and sometimes wind chill effects, tailored to prevent undue alarm in habitually cold areas while highlighting unusual severity elsewhere. Globally, the World Meteorological Organization describes cold waves as marked cooling of the air or invasion of very cold air over a large area.^[8]^[5] In the United States, the National Weather Service (NWS) employs regionally tiered criteria for extreme cold warnings, reflecting latitudinal differences in baseline temperatures. For instance, in the Southeast, cold weather advisories may be issued for temperatures around 28°F (-2°C) or lower (e.g., freeze conditions) or wind chill values near 20°F (-7°C), particularly when affecting sensitive areas. In contrast, the Midwest uses lower thresholds, such as advisories for 10°F (-12°C) or below, with warnings triggered at -20°F (-29°C) or colder due to the region's greater tolerance for subzero conditions during winter. These criteria emphasize duration and wind effects to address risks like hypothermia.^[8]^[10] European definitions often prioritize statistical deviations from long-term averages to capture anomalies in milder continental climates. The UK Met Office, in collaboration with the UK Health Security Agency, issues Cold-Health Alerts based on forecasted mean temperatures, such as low risk at ≤2°C for 48 hours or more, escalating to medium risk for <2°C over 5 days or <0°C for 48 hours; widespread ice and heavy snow forecasts contribute to higher alert levels. In Russia, the Hydrometeorological Service defines cold waves as mean daily temperatures below the 1961–1990 climatic norm lasting five or more consecutive days, with research often using the 3rd percentile of daily mean temperatures; southern regions may apply alerts for temperatures around -10°C for 3+ days.^[11]^[12] In Asia, particularly India, the India Meteorological Department (IMD) adapts criteria to the subcontinent's varied topography and monsoon-influenced climate. A cold wave is declared in the plains when the minimum temperature departs by 4.5°C or more below normal and remains at or below 10°C (50°F) for two consecutive days, focusing on sudden drops that affect densely populated agricultural areas. Hilly regions use a lower absolute threshold of 0°C (32°F) with similar departures.^[13] Seasonal adjustments further refine these criteria, with stricter thresholds applied during warmer months to highlight rarity and impact. In India, "tropical cold waves" during the post-monsoon transition may trigger alerts at minimum temperatures of 10°C (50°F) or below in plains typically above 20°C (68°F), whereas winter criteria are more lenient, requiring larger deviations from norms. Similarly, southern U.S. states lower summer thresholds to emphasize deviations that disrupt accustomed mild winters, while northern regions maintain consistent winter baselines.^[8] Classification systems categorize cold waves by intensity to guide response levels, often using combinations of temperature deviation, duration, and spatial extent. Common tiers include mild (deviation of 3-4.5°C below normal for 2-3 days), severe (4.5-6.5°C below for 3+ days), and extreme (over 6.5°C below or absolute minima like -20°C in temperate zones for extended periods), as seen in IMD protocols where severe events prompt escalated agricultural and health advisories. These gradations prioritize conceptual risk over exhaustive metrics, enabling authorities to scale interventions based on deviation from local norms rather than universal absolutes.^[13]

Causes

Synoptic and Dynamical Causes

Cold waves are primarily triggered by the southward advection of polar or Arctic air masses, facilitated by the development of high-pressure ridges over polar regions that steer cold air equatorward.^[14] This process involves the displacement of dense, cold air from high latitudes into mid-latitude regions, often resulting in abrupt temperature drops over affected areas.^[15] A key dynamical factor is the configuration of the jet stream, where amplified Rossby waves create large-scale undulations that allow intrusions of cold air.^[16] Dips or troughs in the polar jet stream, driven by these planetary-scale waves, weaken the typical west-to-east flow and enable northerly winds to transport frigid air masses southward, intensifying cold outbreaks.^[15] Synoptic-scale high-pressure systems play a central role in these events; for instance, the Siberian High in Eurasia expands and intensifies, blocking warmer air and promoting the outflow of cold continental air toward lower latitudes. Similarly, in North America, the development of a strong high-pressure system over the continent or Greenland facilitates cold air advection by diverting the jet stream and establishing persistent northerly flow patterns.^[14] These setups often lead to associated weather conditions such as clear skies under subsiding air in the high-pressure dome, which enhances radiative cooling at the surface during nighttime.^[17] Northerly winds accompanying the cold air advection further contribute to the chill by replacing milder air masses with polar-sourced ones.^[16] Specific atmospheric patterns, such as omega blocks, exemplify these dynamics, where a high-pressure ridge flanked by two low-pressure systems resembles the Greek letter omega, stalling the jet stream and allowing prolonged cold air incursions on the eastern flank.^[18] Rex blocks, characterized by a high-pressure system positioned poleward of a low-pressure system, similarly immobilize weather systems, fostering extended periods of cold advection in downstream regions.^[17]

Influence of Climate Change

Global warming, through Arctic amplification, has led to faster warming in the Arctic region compared to lower latitudes, weakening the poleward temperature gradient and potentially destabilizing the stratospheric polar vortex. This process can result in more frequent disruptions, such as sudden stratospheric warmings, which allow cold Arctic air to spill into mid-latitudes more readily, increasing the risk of cold outbreaks despite overall warming trends.^[19]^[20]^[21] Observational and modeling studies indicate that while the frequency and intensity of cold extremes have decreased globally since 1950—virtually certain in mid-latitudes like Europe, North America, and Asia—some regions exhibit persistent or variable cold events due to enhanced jet stream meandering. The IPCC AR6 assesses low confidence in direct Arctic influences on mid-latitude cold extremes but medium confidence in circulation changes, such as increased waviness, that can prolong blocking patterns and facilitate intense cold spells in specific areas. For instance, research shows no detectable long-term trend in the magnitude of mid-latitude cold extremes over recent decades, suggesting that variability may sustain occasional severe events even as baselines warm.^[19]^[22]^[23] Climate models project fewer and less intense cold waves in mid-latitudes by 2100 under moderate emissions scenarios, with cold spell durations shortening and probabilities of extreme events dropping by 50–90% in scenarios like SSP2-4.5. However, increased atmospheric variability, including more frequent polar vortex stretching since the 1980s, may shift the geographic focus of cold outbreaks, potentially affecting southern latitudes more. Post-2000 observations highlight this variability, with events like the 2021 Texas cold wave and the January 2025 North American cold wave linked to Arctic-driven stratospheric polar vortex disruptions that amplified cold air advection.^[24]^[25]^[26]^[27]^[28] Emerging 2020s research further emphasizes polar vortex instability, identifying patterns like northwestward shifts in vortex displacements that steer severe cold toward varying U.S. regions, underscoring ongoing uncertainties in predictability; a 2025 study analyzing post-2010 extreme events projects an 80–97% probability that such record cold waves will not recur by 2100 under SSP2-4.5.^[29]

Effects

Human and Health Impacts

Cold waves pose significant direct health risks to humans, primarily through hypothermia, frostbite, and increased cardiovascular strain. Hypothermia occurs when core body temperature drops below 35°C (95°F), leading to impaired physical and mental functions, confusion, and potentially fatal cardiac arrhythmias if untreated. Frostbite, the freezing of skin and underlying tissues, commonly affects extremities like fingers, toes, and ears, causing tissue damage that can result in amputation. Additionally, cold exposure constricts blood vessels, elevating blood pressure and heart rate, which strains the cardiovascular system and heightens the risk of heart attacks and strokes, particularly in those with pre-existing conditions. Globally, cold-related deaths far outnumber heat-related ones; a comprehensive analysis of data from 2000 to 2019 estimated 4.6 million annual cold-attributable deaths compared to 489,000 from heat, making cold approximately nine times deadlier overall.^[30] Certain populations face heightened vulnerability during cold waves due to limited access to shelter, mobility, or medical care. The elderly are particularly at risk because age-related declines in thermoregulation and higher prevalence of chronic illnesses like heart disease exacerbate cold's effects. Homeless individuals and outdoor workers, such as construction laborers or delivery personnel, endure prolonged exposure without adequate protection, increasing their susceptibility to hypothermia and frostbite. Pre-existing conditions, including respiratory diseases and diabetes, further compound these risks by impairing the body's ability to maintain warmth or respond to cold stress.^[31]^[32] Beyond immediate physical threats, cold waves disrupt societal functions and contribute to indirect health burdens. Severe weather often leads to school closures and transportation halts, as icy roads and heavy snow make travel unsafe, isolating communities and interrupting essential services. For instance, in January 2025, winter storms prompted school cancellations for over 1 million students in Texas due to hazardous conditions. These disruptions can exacerbate mental health issues, as prolonged indoor confinement fosters social isolation, loneliness, and heightened anxiety or depression, especially among those already prone to seasonal affective disorder.^[33]^[34] Notable case studies illustrate the human toll of cold waves. In contrast to the well-known 1995 Chicago heat wave, which killed over 700 people, cold events claim far more lives annually worldwide, underscoring underreported risks. The 2018 European cold snap, dubbed "Beast from the East," resulted in over 60 deaths across the continent, primarily from hypothermia among the vulnerable, amid widespread travel chaos. More recently, a 2023 cold snap in Asia led to over 100 fatalities in Afghanistan alone, compounded by heavy snowfall and inadequate shelter in refugee areas. These events highlight how cold waves amplify mortality in underprepared regions.^[35]^[36]

Environmental and Economic Effects

Cold waves exert significant pressure on ecosystems, often leading to mass die-offs of wildlife unadapted to prolonged extreme cold. In the 2021 North American winter storm, particularly in Texas, an estimated 3.8 million fish perished due to plummeting water temperatures that caused hypothermia and oxygen depletion in coastal bays and estuaries.^[37] Similarly, thousands of bats succumbed to the cold, with entire colonies wiped out in caves where they sought refuge, and cold-stunned sea turtles washed ashore, requiring extensive rehabilitation efforts.^[38] These events disrupt food webs, as the loss of prey species like fish affects predators such as birds and marine mammals, potentially leading to cascading ecological imbalances.^[39] Agricultural sectors face severe disruptions from cold waves, resulting in widespread crop failures and livestock losses that threaten food security. Extreme cold can damage fruit crops, as seen in the 1983-1984 U.S. cold wave, which caused severe freezes that devastated citrus orchards in Florida, leading to billions in agricultural damages.^[40] In the Midwest, cold snaps reduce corn and soybean yields by approximately 2.2% and 1.5% per event, respectively, through frost damage to emerging plants and delayed growth cycles.^[41] Livestock are particularly vulnerable, with exposure to subzero temperatures causing hypothermia and increased mortality; during the 2021 Texas event, hundreds of thousands of cattle and poultry died from the freeze, exacerbating supply chain shortages.^[42] Ecologically, cold waves can alter migration patterns and influence invasive species dynamics. Sudden cold outbreaks disrupt the timing of bird and insect migrations, forcing species to expend extra energy or skip breeding seasons, which reduces population resilience over time.^[43] For invasive species, intense cold can act as a natural control by killing off non-native populations less tolerant to low temperatures, such as certain insect pests in temperate regions, potentially slowing their spread in altered climates.^[44] Economically, cold waves strain infrastructure, particularly through failures in water and energy systems. Frozen pipes burst under pressure from expanding ice, as occurred during the 2021 Texas storm, where over 12 million people lost water access due to widespread plumbing failures and treatment plant shutdowns.^[45] Power grids face overloads from surging heating demands and equipment failures in cold weather; the same 2021 event led to blackouts affecting 4.5 million customers, with frozen natural gas infrastructure halting supply and causing cascading failures across power plants.^[46] The financial repercussions of cold waves are substantial, with damages encompassing direct losses and indirect economic disruptions. The 2021 Texas winter storm alone inflicted $80-130 billion in economic losses, including property damage, lost productivity, and emergency responses, marking it as one of the costliest U.S. weather events.^[42] Insurance claims for cold-related damages spike during such events, reflecting heightened payouts for infrastructure repairs and agricultural indemnities. Globally, while comprehensive annual estimates for cold waves are challenging due to varying regional criteria, weather-related extremes—including cold waves—contributed to over $200 billion in economic losses in 2023, with infrastructure vulnerabilities amplifying costs in unprepared regions.^[47]

Countermeasures and Adaptation

Personal and Community Preparedness

Personal preparedness for cold waves begins with individual actions to maintain body heat and minimize exposure to extreme cold. Layering clothing with moisture-wicking base layers, insulating mid-layers, and windproof outer layers helps trap body heat and prevent heat loss, as recommended by the Centers for Disease Control and Prevention (CDC).^[48] Staying indoors during the coldest periods is crucial, limiting outdoor time to brief, necessary trips, and dressing in hats, scarves, gloves, and insulated boots to protect extremities.^[49] When using space heaters for supplemental warmth, place them on a level, hard surface away from flammable materials, never leave them unattended, and ensure they have tip-over protection to avoid fire hazards.^[50] Assembling an emergency kit tailored for cold weather enhances personal resilience, including non-perishable food, water, blankets, flashlights, batteries, a manual can opener, and extra medications to sustain for at least 72 hours.^[51] Insulating homes by sealing drafts around windows and doors with weatherstripping or caulk, and insulating pipes to prevent freezing, are key best practices to retain indoor heat efficiently.^[51] Avoiding travel during peak cold wave conditions reduces risks of vehicle breakdowns or accidents on icy roads; if travel is unavoidable, keep the car fueled, with an emergency kit including blankets, snacks, and a shovel.^[49] Community-level measures complement individual efforts by fostering collective support, such as establishing neighbor check-in programs where residents systematically contact vulnerable individuals like the elderly, children, or those with disabilities to ensure their safety.^[49] Local authorities and organizations like the American Red Cross often open warming centers in schools, community halls, or libraries during prolonged cold snaps, providing heated spaces, hot beverages, and blankets for those without adequate home heating.^[49] Communities can stock public emergency kits with blankets, food, and first-aid supplies for distribution, and coordinate volunteer efforts to assist isolated residents.^[52] Public awareness campaigns play a vital role in education, emphasizing recognition of hypothermia signs such as shivering, confusion, slurred speech, and drowsiness, urging immediate warming and medical attention if observed.^[48] These campaigns, often led by health agencies, promote proactive behaviors like monitoring weather forecasts via mobile apps, such as the American Red Cross Emergency App, which delivers customizable alerts for extreme cold and locates nearby shelters.^[53] By integrating these strategies, individuals and communities can significantly mitigate the health risks posed by cold waves.

Infrastructure and Policy Measures

To enhance infrastructure resilience against cold waves, governments and utilities have prioritized weatherization of buildings and upgrades to energy systems. Weatherizing buildings involves sealing drafts, adding insulation, and installing energy-efficient windows to minimize heat loss during extreme cold, which can reduce energy demand by up to 20-30% in affected areas.^[54] For electrical grids, upgrades include hardening transmission lines against ice accumulation, deploying smart meters for real-time demand monitoring, and integrating battery storage to handle peak heating loads, as cold snaps can increase electricity use by 50% or more in winter.^[55] In the United States, the National Renewable Energy Laboratory (NREL) advocates for grid modernization through distributed energy resources like microgrids, which maintained power for critical facilities during recent cold events by isolating sections from widespread failures.^[56] Smart city technologies, such as automated alert systems linked to weather sensors, further support rapid response by notifying utilities of impending surges in demand.^[57] Policy frameworks at national and subnational levels emphasize coordinated emergency planning and financial incentives to bolster cold wave preparedness. In the United States, the Federal Emergency Management Agency (FEMA) outlines guidelines in its National Preparedness Report for integrating cold weather into broader disaster response strategies, including interagency coordination for resource allocation during blackouts.^[58] Subsidies for home insulation and heating upgrades, such as those under the U.S. Department of Energy's Weatherization Assistance Program, have weatherized over 7 million low-income homes since 1976, reducing vulnerability to cold-related outages. Following the 2021 Texas winter storm, state reforms mandated weatherization of natural gas facilities and power plants, enforced by the Railroad Commission of Texas, to prevent supply disruptions; these rules require operators to test equipment under simulated cold conditions and report compliance annually.^[59] Integration of advanced forecasting into infrastructure management has improved predictive capabilities for cold waves. Artificial intelligence models, such as random forest classifiers, have demonstrated skill in forecasting cold wave days up to 10 days in advance by analyzing historical temperature data and atmospheric patterns, outperforming traditional statistical methods in regions like North America.^[60] The probabilistic AI model GenCast, developed collaboratively by European and U.S. researchers, enhances medium-range forecasts of extreme cold by generating ensemble predictions that capture uncertainty in temperature drops, achieving higher accuracy than conventional systems for extreme cold events.^[61] Internationally, the World Meteorological Organization (WMO) facilitates cooperation through its Early Warnings for All initiative, enabling data sharing among 193 member states to refine cold wave alerts and support cross-border grid stability during transcontinental events.^[62] Long-term adaptation strategies focus on updating building codes and reforming insurance mechanisms to address escalating cold wave risks. Energy conservation codes, such as the 2021 International Energy Conservation Code, incorporate resilience features like enhanced thermal barriers that extend a building's habitability during extreme cold by up to 120% compared to older standards, according to U.S. Department of Energy analyses.^[63] These codes mandate R-value insulation ratings suited to local climates, reducing both energy costs and outage impacts. Insurance reforms, including risk-based premiums that incentivize resilient retrofits, have been adopted in states like California to cover cold-induced property damage, encouraging utilities to invest in preventive infrastructure.

Historical Cold Waves

19th Century and Earlier

The Great Frost of 1740, one of the most severe cold spells in European history, began in late 1739 and persisted through the winter of 1739–1740, with temperatures dropping far below normal across the continent. In Ireland and France, rivers and harbors froze solid, halting transportation and fishing, while prolonged freezing destroyed winter crops and livestock feed, leading to widespread famine in the following year. Historians estimate that the event caused between 310,000 and 480,000 excess deaths in Ireland alone, representing 13–20% of the population, primarily from starvation and exposure, with additional hundreds of thousands perishing in France and other parts of Europe due to similar hardships.^[64] The 1816 "Year Without a Summer" marked another global cold anomaly, triggered by the massive eruption of Mount Tambora in Indonesia in April 1815, which injected vast amounts of ash and sulfur aerosols into the stratosphere, blocking sunlight and causing average global land temperatures to drop by about 1°C. In Europe and North America, this resulted in unseasonably cold summers with frost events in June and July, leading to crop failures of grains and potatoes that exacerbated food shortages and sparked migrations, such as the emigration of New Englanders to the Midwest. The event's impacts were documented in contemporary accounts, including diaries from figures like Lord Byron, who wrote of darkened skies and failed harvests during a stormy summer retreat in Switzerland.^[65]^[66]^[67] In the United States, the winter of 1835–1836 brought extreme cold to the Northeast, culminating in a severe cold snap in December 1835 that froze the Hudson and East Rivers solid, with temperatures plunging to -17°F (-27°C) in New York City and halting maritime traffic. This freeze contributed to the rapid spread of the Great Fire of New York on December 16, as frozen hydrants and ice-covered water sources impeded firefighting efforts, destroying over 600 buildings. Further north, the cold wave of January 1857, known as the "Cold Storm and Great Freeze," afflicted New England with record-low temperatures, including drops to -20°F (-29°C) in Massachusetts and -30°F (-34°C) in Vermont, accompanied by blizzards that buried regions under up to 50 inches of snow and paralyzed rail and road transportation for weeks.^[68]^[69] Prior to the 20th century, records of these cold waves relied heavily on qualitative observations from diaries, ship logs, and church registers, supplemented by rudimentary thermometer readings from early weather stations established in the late 18th century, such as those by the American Philosophical Society. Without modern meteorological networks or forecasting capabilities, societies responded through ad hoc relief efforts, like grain imports during the 1740 famine, but the lack of systematic data often amplified the unpredictability and severity of impacts.^[70]

20th Century

The 20th century marked a period of enhanced documentation of cold waves due to expanding meteorological networks, revealing patterns of increasing societal impacts as populations grew and urbanized. One of the most severe events occurred during the winter of 1935–1936 across North America, where an intense polar outbreak brought record-breaking lows, including −60°F (−51.1°C) in Parshall, North Dakota, on February 15, the state's all-time coldest temperature. This cold wave contributed to at least 273 fatalities from exposure, hypothermia, and related accidents, particularly in the Midwest and Plains states, where transportation and heating systems were overwhelmed. The extreme chill even caused sections of the Mississippi River to freeze solid from St. Louis northward, halting river traffic and exacerbating supply shortages during the Great Depression era.^[71]^[72]^[73] In early 1940, a prolonged cold spell gripped both the U.S. Midwest and Europe amid the onset of World War II, with temperatures plunging to around −25°F (−32°C) in parts of the northern Plains, such as North Dakota, while Europe experienced anomalies down to −40°F (−40°C) in the Baltic region. These conditions disrupted military logistics and civilian life, compounding wartime challenges such as fuel rationing and troop movements; in the U.S., the cold exacerbated infrastructure strains, while in Europe, it delayed spring thaws and hindered early war preparations. The event highlighted emerging vulnerabilities in industrialized regions, where reliance on mechanized transport faltered under subzero conditions.^[74]^[75] The January 1977 cold wave in the Ohio Valley brought sustained lows of −25°F (−32°C) to areas like Cincinnati, triggering a nationwide natural gas crisis that left millions without heat as supplies dwindled amid record demand. Factories shut down, schools closed, and up to 1.5 million workers in Ohio alone were idled, with the shortages linked to prior plant explosions and insufficient reserves; at least 75 deaths were attributed to the freeze nationwide, many from hypothermia among the elderly and vulnerable. This event underscored the growing dependence on fossil fuels in urbanizing areas, amplifying economic disruptions during a period of energy instability.^[76]^[77]^[78] An anomalous cold outbreak struck the U.S. South in January 1985, pushing temperatures to near 0°F (−18°C) in central and northern Florida—unprecedented for the region—and devastating the citrus industry by destroying about 90% of the orange and grapefruit crop, with losses estimated at $2.5 billion. The "freeze of the century" killed off thousands of trees in the citrus belt, shifting production southward and reshaping Florida's agriculture for decades; nationwide, it caused at least 126 fatalities from exposure and related health issues. This event illustrated how even subtropical areas faced escalating risks from polar air intrusions.^[79]^[80]^[81] Throughout the 20th century, cold wave death tolls trended upward in urban centers due to factors like aging populations, higher densities, and urban heat island reversals during cold snaps, which trapped cold air and strained heating systems. Improved records from expanding weather stations captured these shifts, but it was the advent of satellite observations in the 1970s—such as data from NOAA's geostationary and polar-orbiting platforms—that first enabled real-time tracking of cold air masses over vast areas, aiding forecasts and revealing broader atmospheric patterns. These technological advances highlighted how societal expansion amplified vulnerabilities, even as event frequencies varied.^[82]^[83]

21st Century

The 21st century has seen several notable cold waves in North America and Asia, characterized by polar vortex disruptions and amplified by climate variability, leading to significant societal disruptions despite advances in forecasting. These events have tested modern infrastructure, particularly power grids, while highlighting evolving patterns where cold extremes, though less frequent overall, can intensify due to altered atmospheric circulation. Improved early warning systems have mitigated some fatalities compared to earlier eras, but economic and health impacts remain substantial. In late January 2019, a polar vortex event plunged the North American Midwest into extreme cold, with wind chills reaching -50°F (-46°C) in areas like Chicago and Minneapolis, causing widespread flight cancellations across major airports and at least 21 deaths from hypothermia and related accidents.^[84]^[85] The February 2021 Winter Storm Uri in Texas marked one of the most devastating cold waves of the century, with statewide temperatures dropping to around -2°F ( -19°C) and lower in northern regions, leading to catastrophic grid failures that left over 4.5 million people without power for days. This event resulted in 246 deaths, primarily from hypothermia and carbon monoxide poisoning, and inflicted an estimated $195 billion in economic damages from lost productivity, property destruction, and supply chain interruptions.^[86]^[87] A February 2023 cold wave affected North America with Arctic air bringing temperatures and wind chills down to -40°F (-40°C) in the northeastern U.S. and Canada, contributing to at least 11 deaths in the southern states from weather-related incidents. Concurrently, an early-year cold snap in Asia saw record lows of -63.4°F (-53°C) in China's Mohe region and heavy snow across Russia and neighboring areas, with over 100 deaths reported in Afghanistan from the extreme weather, alongside disruptions in China where subzero conditions persisted for weeks.^[88]^[89]^[36]^[90] January 2024 brought a broad Arctic outbreak across the U.S. and Canada, with freezing temperatures and wind chills as low as -30°F (-34°C) from the Rockies to the Midwest, straining power grids and causing outages for thousands amid peak demand. The event hit Midwest agriculture hard, damaging winter crops and delaying planting, with estimated losses contributing to broader sectoral vulnerabilities.^[91]^[92] In January 2025, an intense cold wave gripped the Lower 48 states, with subzero temperatures and wind chills reaching -35°F (-37°C) in the Midwest and records broken in the South, including historic snowfall accumulations of 8–12 inches (20–30 cm) in parts of the Gulf Coast. Infrastructure faced significant strains, including elevated natural gas demand and localized power alerts in regions like Alberta, Canada, though the U.S. grid largely held without widespread blackouts due to prior winterization efforts.^[84]^[93]^[94]^[95] Overall trends in the 21st century indicate fewer cold wave occurrences but greater intensity for those that do happen, linked to climate change-induced weakening of the polar vortex and reduced Arctic sea ice, which allows cold air to surge southward more abruptly. Enhanced meteorological forecasting and preparedness measures, such as grid hardening post-2021, have contributed to declining per-event mortality rates despite these extremes.^[96]^[97]

References

[1]
https://toolkit.climate.gov/hazard/extreme-cold
[2]
What is the Polar Vortex? - National Weather Service
The polar vortex is a large area of low pressure and cold air surrounding both of the Earth's poles. It ALWAYS exists near the poles, but weakens in summer and ...
[3]
Understanding the Arctic polar vortex | NOAA Climate.gov
Mar 5, 2021 · The Arctic polar vortex is a band of strong westerly winds that forms in the stratosphere between about 10 and 30 miles above the North Pole every winter.
[4]
Longwaves and Shortwaves - NOAA
Nov 1, 2024 · Rossby waves help to transfer heat from the tropics toward the poles and cold air from the poles toward the tropics trying to return the ...
[5]
[PDF] Guidelines on the Definition and Characterization of Extreme ...
A cold wave is a meteorological event generally characterized by a sharp drop in air temperature near the Earth's surface, leading to extremely low values that ...
[6]
Cold waves are getting milder in the northern midlatitudes
An analysis of the entire northern midlatitudes confirms the steady decrease in severity and frequency of cold waves over the last decades in the observations.
[7]
Cold Wave (MH0502) - UNDRR
A cold wave is a period of marked and unusual cold weather characterised by a sharp and significant drop in air temperatures near the surface (maximum, ...
[8]
Hoist a flag for cold waves and other weather conditions - NOAA
Jan 6, 2025 · In the late 19th and early 20th centuries, signal flags were used to alert U.S. citizens to weather conditions.
[9]
Extreme Cold Warning vs Watch and Cold Weather Advisory
A Cold Weather Advisory is issued for dangerously cold conditions that are not expected to reach warning criteria. Be sure you and your loved ones dress ...Missing: wave | Show results with:wave
[10]
Cold Weather Product Change Overview - National Weather Service
The thresholds for temperature and wind chills are in "tiers" from coldest in the north to warmest in the CONUS. · These are based on climatology and what ...
[11]
[PDF] Weather-health alerting system - user guide - GOV.UK
Oct 31, 2023 · During both the summer and winter seasons, UKHSA and the Met Office monitor the weather forecasts and where episodes of hot or cold weather are ...
[12]
Health Risks to the Russian Population from Temperature Extremes ...
Based on long-term research, it was determined that heat (cold) waves incorporate periods with an excess of the 97(3)% percentile of the distribution of mean ...
[13]
[PDF] The cold wave conditions signify a certain amount of fall of - IMD Pune
When minimum temperature departure is -4.5°C or less over a station, “Cold. Wave” may be described if the minimum temperature is 150C or less. Annual Disaster ...
[14]
[PDF] Processes Contributing to North American Cold Air Outbreaks ...
We find that long- wave radiative cooling and vertical mixing are the two domi- nant contributors to temperature evolution along both CAO and MTE trajectories, ...
[15]
Variability of the Cold Season Climate in Central Asia. Part I
Strongly negative temperature anomalies are caused by northerly anomalies of the wind field and an associated advection of polar air masses. Positive anomalies ...
[16]
Atmospheric blocking events in the North Atlantic: trends and links to ...
Jan 5, 2021 · ... Rossby waves (Mann et al. 2017), disrupting the passage of the ... They can also produce strong advection of polar air on their eastern ...
[17]
Basic Wave Patterns - NOAA
May 18, 2023 · Rex blocks are characterized by a high-pressure system located pole-ward of a low-pressure system. The Rex block will remain nearly stationary ...
[18]
Synoptic dynamics of cold waves over north India - ScienceDirect.com
Cold waves are classified into normal and intense (NCWs and ICWs) based on intensity and we examine the underlying mechanisms of formation and their atmospheric ...<|separator|>
[19]
Chapter 11: Weather and Climate Extreme Events in a Changing ...
Warm spells/heatwaves: increases in frequency or intensity over most land areas. Cold spells/cold waves: decreases in frequency or intensity over most land ...
[20]
Evidence linking rapid Arctic warming to mid-latitude weather patterns
In this study, new metrics and evidence are presented that suggest disproportionate Arctic warming—and resulting weakening of the poleward temperature gradient ...
[21]
Q&A: How is Arctic warming linked to the 'polar vortex' and other ...
Jan 31, 2019 · A growing body of research has proposed ways in which rapid Arctic warming can lead to harsh winters, summer heatwaves and even floods and droughts across the ...<|separator|>
[22]
No detectable trend in mid-latitude cold extremes during the recent ...
Sep 28, 2023 · It is widely accepted that Arctic amplification—accelerated Arctic warming—will increasingly moderate cold air outbreaks to the ...
[23]
Understanding the Arctic polar vortex | NOAA Climate.gov
Mar 5, 2021 · The Arctic polar vortex is a band of strong westerly winds that forms in the stratosphere between about 10 and 30 miles above the North Pole every winter.
[24]
[PDF] Weather and Climate Extreme Events in a Changing Climate - IPCC
... climate extremes generally scale with global warming. New evidence strengthens the conclusion from the IPCC Special Report on. Global Warming of 1.5°C (SR1.5) ...
[25]
Recent Extreme Cold Waves are Likely Not to Happen Again This ...
To address this question, we assess the probability that an ECW12-like cold wave ... Glossary of Meteorology · State of the Climate · Explaining Extreme Events.
[26]
Linking Arctic variability and change with extreme winter weather in ...
Sep 1, 2021 · Therefore, Arctic change is likely contributing to the increasing frequency of SPV stretching events, including one just prior to the Texas cold ...
[27]
Cold-air outbreaks in the continental US: Connections with ... - Science
Jul 11, 2025 · In this study, we analyze both the upper and lower polar stratosphere for links to extreme winter cold and snow in the continental US, finding two SPV ...
[28]
https://journals.plos.org/climate/article?id=10.1371/journal.pclm.0000679
[29]
8.2.1.2 Cold-waves - AR4 WGII Chapter 8: Human Health - IPCC
Accidental cold exposure occurs mainly outdoors, among socially deprived people (alcoholics, the homeless), workers, and the elderly in temperate and cold ...<|control11|><|separator|>
[30]
Extreme cold - Impacts | Ouranos
Key population groups that are particularly vulnerable to extreme cold include: The elderly. Outdoor workers. People experiencing homelessness. Residents of ...
[31]
Winter storms cause schools to cancel classes across the Southern US
Jan 9, 2025 · A powerful winter storm brought heavy snow and icy conditions to parts of the US South on Thursday, forcing officials to close schools, cancel flights and warn ...
[32]
Seasonal affective disorder: Not just the winter blues
Jan 5, 2023 · People tend to stay indoors more often when it's cold and dark. This can increase isolation and decrease the opportunity to share enjoyable ...Missing: wave issues
[33]
Europe severe weather: Death toll rises amid freeze - BBC
Mar 2, 2018 · Over the past week, the cold weather has killed seven in Slovakia, six in the Czech Republic, five each in Lithuania and France (excluding the ...Missing: wave | Show results with:wave
[34]
Japan and North Korea sound warning as deadly cold snap sweeps ...
Jan 25, 2023 · Extreme weather kills at least one person in Japan and more than 100 in Afghanistan while parts of China hit record low temperatures.
[35]
Public Help Sought to Report Fish and Wildlife Impacted by Winter ...
Feb 23, 2021 · Some of the wildlife species impacted by the storm include exotic, non-native ungulates like axis deer, blackbuck and nilgai antelope that ...
[36]
Snow-mageddon - Texas Parks & Wildlife Magazine
from cold-stunned turtles to saltwater fish kills to bat die-offs — was struggling to survive the ...
[37]
Impacts | U.S. Fish & Wildlife Service
Climate change has very likely increased the size, intensity, and number of wildfires, insect outbreaks, disease outbreaks, and tree mortality.Missing: vortex | Show results with:vortex
[38]
Billion-Dollar Weather and Climate Disasters | Events
Associated cold wave over much of the U.S. causes ... Central and eastern U.S. drought/heat wave caused damage to agriculture and other related industries.
[39]
https://www.fws.gov/initiative/climate-change/impacts
[40]
Cost of Texas' 2021 deep freeze justifies weatherization
Apr 15, 2021 · Early estimates indicate that the freeze and outage may cost the Texas economy $80 billion–$130 billion in direct and indirect economic loss.
[41]
Weather Whiplash: How Extreme Winters Impact Wildlife - Tandem ...
Feb 1, 2023 · Migratory species have had their patterns disrupted and rerouted due to unusually mild winters and extremely cold winters alike, and species ...
[42]
The effect of climate change on invasive crop pests across biomes
Feb 28, 2022 · Colder winters may delay and reduce the outbreaks of some pest species. For example, a negative impact of cold winter days (Tmin <−5°C) on ...Missing: credible | Show results with:credible
[43]
Texas Water Crisis: Frozen Pipes, Cracked Wells and Offline ...
Feb 20, 2021 · The director of Austin Water, Greg Meszaros, said that plummeting temperatures caused water mains to break and pipes to burst, spurring an ...
[44]
Cascading risks: Understanding the 2021 winter blackout in Texas
AccuWeather estimated economic losses from lost output and damage to be $130 billion in Texas alone and $155 billion for the country as a whole [4].
[45]
[PDF] The economic cost of extreme weather events
Nov 7, 2024 · Based on nearly 4,000 events across six continents from 2014 to 2023, we estimate economic losses from these events at $2 trillion in 2023 ...
[46]
Safety Guidelines: During & After a Winter Storm - CDC
Feb 7, 2024 · Keep a water supply. Extreme cold can cause water pipes in your home to freeze and sometimes rupture or break. When you are expecting very cold ...Missing: community waves
[47]
Winter Storm Preparedness
### Summary of Winter Storm Preparedness Tips from Red Cross
[48]
https://www.cdc.gov/winter-weather/safety/stay-safe-during-after-a-winter-storm-safety.html
[49]
Preparing for a Winter Storm | Winter Weather - CDC
Feb 7, 2024 · Weatherproof your home. · Insulate any water lines that run along exterior walls so your water supply will be less likely to freeze. · Caulk and ...Be Prepared For Winter... · Get Your Home Ready · Get Your Car Ready
[50]
https://www.redcross.org/content/dam/redcross/get-help/pdfs/winter-storm/EN_Winter-Storm-Preparedness-Checklist.pdf
[51]
Cold waves and cold weather | Epidemic Control Toolkit
Aug 8, 2023 · People living in precarious types of shelter or people experiencing homelessness are at higher risk. People that practice winter sports, infants ...
[52]
https://epidemics.ifrc.org/manager/disaster/cold-waves-and-cold-weather
[53]
5 ways to make buildings climate change resilient - UNEP
Jul 7, 2021 · Communities can create urban forests and green spaces to reduce heatwaves in cities as trees and other plants cool the surrounding environment ...
[54]
Climate Resilience – Analysis - IEA
Apr 12, 2021 · This report provides an overview of the climate impacts on electricity systems. It describes how climate change affects each segment of the electricity value ...
[55]
Extreme Weather Events | Grid Modernization - NREL
Jun 30, 2025 · Today, weather typically stresses grid resilience by creating peak loads. Cold waves increase heating demand, and heat waves elevate cooling ...
[56]
How to make infrastructure more resilient against climate change
Jan 3, 2022 · Improving resilience before or following a hazard event should engage physical infrastructure and social systems with adaptive capacity to ...
[57]
[PDF] 2023 National Preparedness Report - FEMA
Dec 1, 2023 · Policy, Guidance, and Governance: Plans should include frameworks for senior leadership on how to handle complex barriers during incidents ...
[58]
Texas adopts new natural gas weatherization rules 18 months after ...
Aug 30, 2022 · Critics are skeptical about whether the new rules by the Railroad Commission will prevent another catastrophe like the power grid disaster ...
[59]
Probabilistic weather forecasting with machine learning - Nature
Dec 4, 2024 · Here we introduce GenCast, a probabilistic weather model with greater skill and speed than the top operational medium-range weather forecast in the world, ENS.
[60]
Extreme weather - World Meteorological Organization WMO
Examples of extreme weather and climate events include, but are not limited to, heatwaves, cold waves, heavy precipitation, drought, tornadoes and tropical ...
[61]
National Labs Study Finds Updated Building Energy Codes Save ...
Jul 25, 2023 · DOE analysis finds the 2021 International Energy Conservation Code can reduce deaths from extreme heat by as much as 80 percent.
[62]
On this day in history… a forgotten Irish Famine started.
Dec 29, 2024 · ... Great Frost scholar David Dickson has estimated that the excess mortality was between 310,000 and 480,000 on a population of 2.4 million.
[63]
Tambora 1815 as a test case for high impact volcanic eruptions
The Tambora eruption caused cooling, a "Year without a Summer", and a 1°C drop in global land temperature, with increased sea ice.
[64]
Mount Tambora and the Year Without a Summer
The Year Without a Summer had many impacts in Europe and North America. Crops were killed - either by frost or a lack of sunshine. This caused food to be scarce ...
[65]
1816 - The Year Without Summer (U.S. National Park Service)
Apr 4, 2023 · The eruption of Mount Tambora in Indonesia in 1815 triggered a change in the global climate. The heavier material fell to the ground and the ...
[66]
New York City (NYC) The Fire of 1835 - Baruch College
Water supplies were running low; to make matters more desperate, -17 degree weather had caused a thick sheet of ice to form over the East River. Even after ...
[67]
The Cold Storm and Great Freeze of 1857 - New England Historical ...
The weather in New England remained mild until mid-December, though plenty of snow had fallen. Then on December 17 the temperature plummeted to 12 below zero in ...
[68]
[PDF] Climactic Effects of the 1815 Eruption of Tambora
The 1815 eruption caused the "Year Without a Summer" in some regions, massive crop failure, and widespread famine, disease and social stress.
[69]
1936 — Feb 1-28, Polar Coldwaves, Snow, Blizzards, Snowslides ...
New low mean temperature records were established in eight States, namely, Iowa, 6.0° departure from normal, -16.3°; Missouri, -5.5° departure, -17.8°; Montana, ...
[70]
THE COLD WINTER OF 1935-36 - jstor
North Dakota: Revision of data must now be made to include a new low record for North Dakota, —60° at Parshall on Feb. 15, 1936. More over, Feb., 1936, with ...
[71]
A LOOK BACK: US Winter Of 1935-36 : MarkVoganWeather.com
Dec 20, 2015 · The 1936 cold wave began in the Plains in November of 1935, when temperatures were well below normal in all areas west of the Mississippi, and ...Missing: details | Show results with:details
[72]
Four months' war brewed arctic winter - war changes climate
The 13th of January 1940: Bitterest cold wave for years, which sent temperatures in the Baltic countries down to as low as 40 degrees below zero Fahrenheit, ...<|separator|>
[73]
Europe in Ice-Age — January 1940 — Why? | by Dr. Arnd Bernaerts
Jan 9, 2021 · Average January winter temperatures in Western Europe are above zero degrees Celsius, since the end of the Little Ice Age (~1850).
[74]
COLD WAVE CAUSES ENERGY SHORTAGES AND PLANT ...
Jan 18, 1977 · Yesterday's record tempratures—such as 24 degrees below zero in Cincinnati—represented a continuation of abnormal cold that has run down natural ...Missing: Valley | Show results with:Valley
[75]
[PDF] Severe winter cold causes 75 deaths
Feb 1, 1977 · The severe cold blitz that has left at least 75 Americans dead and sliced deeply into natural gas supplies has forced millions of.
[76]
The 1977 natural gas shortage - Toledo History Box
Dec 20, 2018 · The shortage kicked off on January 10, when an explosion at the Columbia LNG Corp. synthetic gas plant at Green Springs, southeast of Fremont, ...
[77]
'FREEZE OF THE CENTURY' DAMAGES 90% OF THE CITRUS ...
Jan 23, 1985 · Two days of record-breaking cold damaged nine-tenths of Florida's orange and grapefruit crop, state officials reported today.
[78]
January 1985 Record-breaking Cold - National Weather Service
Jan 12, 2015 · Florida cold snap freezes citrus crops, North warmer ... New York Times: 'Freeze of the Century' Damages 90% of the Citrus Crop in Florida.
[79]
January 21, 1985 Coldest Day of the 20th Century in Eastern North ...
At least 126 deaths were blamed on the cold snap and 90 percent of the citrus crop in Florida was destroyed in what the state called the "Freeze of the Century ...Missing: wave 0°
[80]
The Social Burden of Weather and Climate Hazards
There is strong evidence for an increasing social vulnerability to temperature extremes (cold and heat waves). This is linked to a number of demographic ...
[81]
20th Century Reanalysis - Physical Sciences Laboratory - NOAA
The NOAA-CIRES-DOE Twentieth Century Reanalysis (20CR) project has generated a four-dimensional global atmospheric dataset of weather spanning 1806 to 2015.Missing: deaths | Show results with:deaths
[82]
January 19-24, 2025: Multiday Cold Spell Featuring Sub-Zero ...
Jan 19, 2025 · January 19-24, 2025: Multiday Cold Spell Featuring Sub-Zero Temperatures and Wind Chills as Cold as -35°F · Wind chill values dropped below 0°F ...
[83]
https://psl.noaa.gov/data/20thC_Rean/
[84]
Final Report on February 2021 Freeze Underscores Winterization ...
Nov 16, 2021 · More than 4.5 million people in Texas lost power – some for as long as four days. Tragically, the loss of electricity caused the deaths of ...
[85]
The Texas Storm That Proved the Need for Grid Investments
Feb 9, 2022 · Tragically, at least 246 people died. The state's economy suffered $195 billion in damages, making it the largest disaster in state history. The ...
[86]
Brutal cold seizes northeast U.S., shattering record lows | Reuters
Feb 4, 2023 · High winds and low temperatures created dangerous conditions and caused the death of an infant in Massachusetts.
[87]
11 died in Texas 2023 winter storm - then a brutal cold snap struck ...
Feb 6, 2023 · Eight people died in Texas, two in Oklahoma and one in Arkansas due to bad weather conditions since Monday, February 1st.
[88]
Polar Vortex Drives a Cold Snap in Asia - The New York Times
Jan 31, 2023 · At least three deaths in Japan this week were also linked to cold weather, a cabinet secretary told reporters on Wednesday. Heavy snow has ...
[89]
Arctic blast continues to sweep entire US setting record-low ...
Jan 16, 2024 · The National Weather Service said wind chills were expected to push temperatures to -30F (-34C) from the northern Rockies to northern Kansas and ...
[90]
Severe US cold snap prompts peak power and natural gas demand
Jan 17, 2024 · Freezing temperatures in several U.S. regions triggered peak power demand in parts of the country on Wednesday, after homes and businesses ...
[91]
Assessing the U.S. Climate in January 2025 | News
Feb 10, 2025 · The average temperature of the contiguous US in January was 29.2°F, 0.9°F below average, ranking in the coolest third of the 131-year record and the coldest ...Missing: infrastructure strains
[92]
Historic January 2025 snowstorm in the Southern U.S. - Climate
Jan 29, 2025 · The National Weather Service office in Lake Charles, LA, issued its first blizzard warnings ever for portions of the state. On January 21 ...
[93]
FERC, NERC Issue Report on System Performance During the ...
Apr 17, 2025 · The country's Bulk-Power System performed well during successive cold weather events in January 2025, without major issues in either the natural gas or ...
[94]
[PDF] Intensity and dynamics of extreme cold spells of the 21st century in ...
Oct 16, 2025 · Cold extremes have significant impacts on society, with cold weather being linked to excess mortality and morbidity (Con- lon et al., 2011; ...
[95]
Attributing climate and weather extremes to Northern Hemisphere ...
May 3, 2025 · Changes in NH sea ice and snow have been linked with a variety of climate and weather extremes including cold spells, heatwaves, droughts and wildfires.