It was a cold April morning in the mountains of western North Carolina in the United States. It was raining lightly, with temperatures above 40 degrees F (4 degrees C). The rain started to pick up. The temperature dropped dramatically in minutes, down to 32 degrees F (0 degrees C). The rain changed to snow. Then a flash lit the sky — lightning! This was a thunder snowstorm.
Blinding snow filled the sky, dropping the visibility at the Asheville Airport to 1/4 mile (400 m) at times. It snowed heavily for an hour, with numerous lightning flashes. Four inches (10.2 cm) of snow accumulated. Even though the ground was warm, snow covered everything. Just as quickly as it had started, the storm ended. Temperatures warmed back up above freezing, and the snow melted nearly as fast as it had fallen.
Thundersnow is defined as a snowstorm accompanied by lightning and thunder — a type of convective precipitation with below-freezing temperatures. We normally think of convective showers and …
