blizzards

A blizzard is a severe winter storm characterized by a combination of heavy snowfall, strong winds, and very low visibility. In the United States, the National Weather Service defines a blizzard as sustained winds or frequent gusts of 35 mph (56 km/h) or greater, with visibility reduced to 1/4 mile (400 meters) or less, lasting for at least three hours. Snowfall amount is not a formal criterion, but heavy snow and blowing snow are typical features, often producing whiteout conditions and large snowdrifts.

Blizzards form when a strong low-pressure system or extratropical cyclone draws in cold air from the north and moisture from the south. The interaction leads to sustained snowfall, high winds, and wind-driven snow that reduces visibility well beyond the snow itself. While most common in colder regions, blizzards can occur in many temperate climates during winter.

Impacts include transportation disruption, with road closures, flight cancellations, and hazardous driving conditions. Power outages can result from wind and heavy snow, and exposed individuals face risks of hypothermia and frostbite. Drifting snow can bury structures, create impassable roads, and hinder emergency response.

Forecasting relies on weather satellites, radar, surface observations, and computer models to identify potential blizzard conditions. Warnings and advisories are issued to inform the public about expected snowfall, winds, and visibility. Preparedness emphasizes staying indoors, stocking supplies, winterizing vehicles, and avoiding travel during blizzard conditions. In mountainous or exposed areas, avalanche risk can increase when large snow accumulates.