Winter storms in focus: scale, duration and rising losses

A large and complex winter storm is forecast to affect much of the central and eastern United States over the coming days. U.S. weather authorities indicate that an entrenched Arctic air mass interacting with developing low pressure is likely to produce heavy snow north of the temperature boundary and freezing rain and ice to the south, affecting regions from the Southern Plains through the Ohio Valley, Appalachians, Mid-Atlantic and Northeast.

Forecast guidance points to heavy snowfall totals — locally exceeding 12 inches — across parts of the Midwest, Mid-Atlantic and Northeast, while ice accumulations in portions of the southern U.S. could result in hazardous travel, downed trees and power outages. Behind the storm, dangerously cold temperatures are expected to persist across large areas, increasing the risk of frozen and burst pipes and placing sustained stress on power, water and transportation infrastructure.

While the exact impacts will depend on the storm’s evolution, the breadth of the forecast highlights a defining characteristic of winter storms: their ability to affect large populations and multiple economic sectors simultaneously, often across regions with very different levels of cold-weather preparedness.

Winter storms remain a significant — and often underestimated — natural peril across Europe and North America. Characterised by heavy snow, ice, strong winds and extreme cold, these systems can disrupt transport, utilities and economic activity across vast geographic areas, placing strain on communities, infrastructure and insurance markets alike.

Within catastrophe risk frameworks, winter storms are classified as primary perils, alongside hurricanes and earthquakes. While their peak wind speeds are generally lower than those of tropical cyclones, their broad footprint, multi-day duration and interaction with exposed infrastructure mean that even moderate events can generate substantial aggregated impacts — particularly where population density and insured values are high.

In the United States, insured losses from winter storms have been elevated in recent years.

These recent elevated losses reflect severe individual events and broader exposure growth.

Recent experience also shows that extreme cold, rather than snowfall or wind alone, has been the dominant driver of the largest winter-storm losses. Prolonged freezing temperatures materially increase the likelihood of widespread pipe failures, water damage and business interruption — particularly when combined with power outages or fuel-supply constraints.

The February 2021 Arctic outbreak in the south-central U.S. illustrated how infrastructure stress can act as a loss multiplier, transforming a cold-weather event into a systemic insurance loss through cascading impacts. A similar dynamic, though on a continental scale, was observed during the December 2022 freeze, which affected more than 40 U.S. states simultaneously and generated substantial insured losses across multiple lines of business.

The upward trend in winter-storm losses reflects more than meteorological variability. Accumulation of exposed assets, urbanisation, rising construction and repair costs, and increasingly interconnected infrastructure systems are all amplifying loss potential.

Duration is a critical severity factor. The longer sub-freezing temperatures persist, the greater the probability of pipe failures, outage-driven loss amplification and cascading business interruption. Even when individual claims are moderate, high-frequency freeze-related losses can accumulate rapidly across large geographies, creating material portfolio-level impacts.

These dynamics help explain why winter storms — often perceived as lower-severity hazards — can become high-impact loss drivers when viewed through the lens of aggregation, exposure growth and infrastructure interdependence.

Swiss Re has long been a global leader in natural catastrophe reinsurance, climate risk analytics and risk transfer solutions. Drawing on decades of peril-specific expertise, advanced catastrophe models and high-resolution hazard data, Swiss Re supports clients in understanding, quantifying and managing winter-storm risk within increasingly complex portfolios.

Through reinsurance structures, accumulation management and data-driven insights, Swiss Re helps insurers and institutional partners strengthen resilience.