Thundersnow

Thundersnow is a meteorological phenomenon in which thunder and lightning occur during a snowstorm or heavy snow event. It results from the same electrical processes that generate lightning in ordinary thunderstorms, but within a winter precipitation environment. The snow itself does not prevent lightning; rather, the storm’s convective dynamics produce charge separation and discharges within a cloud or between clouds.

Conditions favor thundersnow when cold air aloft and strong surface lift create instability and vigorous updrafts inside a winter storm, such as a nor’easter or lake-effect snow band. Adequate moisture and lift enable towering clouds to develop charged regions. The lightning can be cloud-to-cloud or cloud-to-ground; ground strikes do occur but are less common than in warm-season thunderstorms.

Audible thunder is often muted by the falling snow and may be heard only briefly or not at all at distance, while flashes can illuminate snow-filled skies. Snow or blizzard conditions can make visibility poor, but lightning can still be visible.

Instances are relatively rare but have been documented in regions with strong winter storm activity, including the Great Lakes and northeastern United States, eastern Canada, and parts of northern Europe. Thundersnow may accompany heavy snowfall rates under intense convective bands.

Detection and safety: Meteorological observations and lightning networks confirm events; radar may not show typical thunderstorm signatures. If thundersnow is observed, seek shelter indoors and avoid exposed areas, as lightning can strike even when the sky is obscured by snow.