A video captured at Loveland Ski Area in Colorado on October 14th shows an unusual early-season weather phenomenon at approximately 11,000 feet. The footage captures thundersnow, a relatively rare event in which lightning and thunder occur during a snowstorm.
Thunderstorms are typically associated with warmer weather, but the right atmospheric conditions can produce lightning even when snow is falling.
What Is Thundersnow?
Thundersnow occurs when a snowstorm develops enough atmospheric instability and moisture to support thunderstorm activity. These conditions can develop above a warm front, where rising air helps create the environment needed for thunderstorms to form.
The phenomenon is uncommon because winter storms generally have less atmospheric instability than typical thunderstorms. However when the necessary ingredients come together, lightning can occur alongside snowfall, producing thunder in conditions more commonly associated with quiet winter weather.
Thundersnow can also develop during lake-effect snowstorms downstream of the Great Salt Lake and the Great Lakes. When cold air moves over relatively warmer lake water, it can trigger intense, localized snowfall and occasionally create the conditions needed for lightning.
The video caption specifically describes the October 14th event near Loveland as more of “thunder graupel” than thundersnow. Graupel forms when supercooled water droplets freeze onto falling snowflakes, creating small, soft pellets of ice.