Winter precipitation during the January 2026 North American storm likely amplified by human-driven climate change

Contact Authors

• Davide Faranda (IPSL-CNRS, France) - davide.faranda@lsce.ipsl.fr  - EN/FR/IT

• Tommaso Alberti (INGV, Italy) - tommaso.alberti@ingv.it - EN/IT

• Haosu Tang (University of Sheffield, UK) – haosu.tang@sheffield.ac.uk  – ZH/EN

Citation

• Faranda, D., Tang, H., & Alberti, T. (2026). Winter precipitation during the January 2026 North American storm likely amplified by human-driven climate change. ClimaMeter, Institut Pierre Simon Laplace, CNRS. https://doi.org/10.5281/zenodo.18402240

Press Summary

• Winter storms similar to those of January 2026 in North America are associated with locally up to 5 °C warmer temperatures and up to 6 mm/day (~20%) higher precipitation than in past decades, which, under near-freezing conditions, translates into substantially heavier snowfall and freezing rain.

• The January 2026 North American winter storm was exceptionally rare, standing out in the historical record.

• We mostly ascribe the increase of precipitation in the January 2026 North American winter storm to human-driven climate change, and natural climate variability likely played a minor role.

The North American winter storm of 24–25 January 2026 affected large parts of the central and eastern United States and southeastern Canada, bringing exceptionally severe winter weather to densely populated regions. The storm was characterised by heavy snowfall, widespread freezing rain, and strong winds, leading to blizzard conditions in some areas and hazardous ice accretion in others. Snow accumulations locally exceeded 30–40 cm across parts of the Midwest and Northeast, while freezing rain caused significant ice buildup on trees, power lines, and transport infrastructure, creating hazardous travel conditions and widespread disruption. The socio-economic impacts of the storm were severe. Power outages affected more than one million customers, particularly in southern and midwestern states where ice damage caused extensive failures of electricity networks. Transport systems were heavily disrupted, with more than 11,000 flights cancelled and major airports temporarily suspending operations during the peak of the storm. Numerous roads and highways were closed due to snow, ice, and fallen debris, while several states issued emergency declarations and ordered the closure of schools, public buildings, and non-essential activities as a preventive measure. Despite advance forecasts and early warnings, the storm resulted in multiple fatalities linked to traffic accidents, exposure to extreme cold, and other storm-related incidents, underscoring the high vulnerability of infrastructure and populations to compound winter hazards. Local authorities reported that some communities were temporarily isolated and that recovery efforts, particularly in areas affected by prolonged power outages, would take weeks. The January 2026 winter storm highlighted the systemic risks posed by large-scale winter extremes to energy systems, transport networks, and emergency response capacities across North America.

The meteorological conditions associated with the North American winter storm of 24–25 January 2026 were characterised by strong positive surface pressure anomalies, exceeding +10 to +15 hPa over large parts of central and eastern North America. This pattern reflects the presence of an intense and persistent high-pressure system interacting with a deep frontal zone, leading to strong pressure gradients across the affected region. This configuration could be also linked to the breaking of the polar vortex dynamics creating intense cold spells over the US and also extending towards Europe. Near-surface temperature anomalies were predominantly negative, with values locally exceeding −5 to −10 °C, consistent with widespread cold-air advection from high latitudes. Precipitation during the event was extensive, with daily totals locally reaching 40–60 mm, particularly along the storm track from the central United States toward the Northeast, indicative of strong moisture convergence along frontal boundaries. Near-surface wind speeds were elevated over a broad area, locally exceeding 50–60 km/h, contributing to blizzard conditions and enhancing the impacts of snowfall and freezing precipitation. The combination of anomalously high surface pressure, strong thermal gradients, and enhanced moisture transport underscores the role of a highly amplified large-scale circulation pattern in driving the exceptional severity of this winter storm. 

Climate and Data Background for the Analysis

The IPCC AR6 WG1 report discusses the significant impact of climate change on the frequency and intensity of cold outbreaks in North America. According to the IPCC, North America has experienced a marked warming trend that has fundamentally altered the nature of temperature extremes. While episodes of extreme cold have become less frequent overall, they still occur and now unfold in a very different atmospheric context than in the past. Historically, cold outbreaks were typically associated with dry continental air masses. Today, however, extreme cold increasingly interacts with a warmer and more moisture-laden atmosphere. As a result, when cold air incursions do occur, they are more likely to produce heavier snowfall and a higher incidence of freezing rain rather than dry cold conditions. These evolving cold-season processes have important implications for impacts, increasing the risks associated with winter storms, ice accumulation, and infrastructure disruption, even as extreme cold events become less common overall.

Our analysis approach rests on identifying weather situations similar to those of the event of interest having been observed in the past. For the January 2026  North American winter storm, we have medium-to-high confidence in the robustness of our approach given the available climate data.

ClimaMeter Analysis 

We analyse here (see Methodology for more details) how events similar to the January 2026 North American winter storm have changed in the present (1988–2025) compared to what they would have looked like if they had occurred in the past (1950-1987)  in the region [-95°E -65°E 35°N 50°N].  Surface pressure changes show mostly unchanged patterns. Temperature changes indicate that similar events have not undergone major large-scale modifications, although locally warmer conditions of up to approximately +5 °C are detected in the present compared to the past over parts of the eastern United States. Precipitation changes show that present-day events are wetter than in the past, with increases of up to 6 mm/day over the most affected regions. Wind speed changes display weak and spatially heterogeneous signals, with changes generally remaining within ±6 km/h, indicating no clear large-scale intensification or weakening of near-surface winds, apart for increased sustained winds over the New York coast.

These results suggest that similar winter storm events have slightly evolved in a manner consistent with expectations under a warming climate, mainly through enhanced precipitation and locally warmer temperatures. In winter storm conditions, warmer air can hold more moisture, increasing the availability of water vapour for heavier snowfall and freezing rain when temperatures remain near or below freezing. This mechanism helps explain why precipitation intensifies even when large-scale circulation changes remain limited. The analysis of similar past events indicates a slight shift in seasonality, with such events occurring more frequently in January in recent decades compared to the past, when they were occurring more in February. No analogues have been found in December although it was included in the analyses. The analysis of changes in urban areas shows that, for similar events, Chicago, New York and Philadelphia are significantly warmer and wetter and New York and Philadelphia also experience windier conditions. 

Finally, we find that sources of natural climate variability – such as the El Nino Southern Oscillation, the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation – may have not influenced the event. This suggests that the changes we see in the event compared to the past are mainly due to human driven climate change.

Conclusion

Based on the above, we conclude that low-pressure patterns similar to those causing the January 2026 North American winter storm are at present associated with locally warmer temperatures of up to 5 °C and higher precipitation rates of up to 6 mm/day (≈20%), which, under near-freezing conditions, translate into substantially heavier snowfall and freezing rain. We interpret this as an event driven by very rare meteorological conditions whose intensity has been amplified by human-driven climate change, through a warmer background state and enhanced precipitation.