Thundersnow that happens when thunder and lightning occur during snowfall. The rare weather event can be helpful for predicting a larger storm.
Less than one percent of all snowstorms are associated with thunder, according to ABC News. They require just the right mix of atmospheric instability and upward motion of warm air that make both snowstorms and thunder unique.
"Thunder and lightning existing in the storm are usually a symptom of something else," Patrick Market, associate professor of atmospheric science at the University of Missouri, told ABC News. "That's usually a harbinger of somebody getting a significant snowfall later on."
According to AccuWeather, "thundersnow" is the name given to a snowstorm that is accompanied by thunder and lightning. Thunderstorms are significantly more likely in the summer when instability is in the air, along with lift and moisture.
The necessary instability for a thunderstorm is less likely in the winter, as the air below needs to be cold enough for snow, yet warmer than the air above it.
However, when the right conditions are met, thunder and lightning can be produced during a winter snow storm. Since the snow can muffle the sound of thunder, you're more likely to notice it if you are within three miles of the lightning strike.