A brief explanation of winter thunderstorms.

Thundersnow: When the snow rumbles

2/9/13

With blizzards occurring in the northeast, we have heard quite a bit about the accompanying thundersnow. But what is thundersnow? Just like it sounds, thundersnow is a winter thunderstorm (also known as a thunder snowstorm). We had one here in southwest Virginia just a couple of weeks ago.

Conditions for the perfect storm

Despite the recent occurrences, thundersnow is actually a rare event. Winter thunderstorms develop similarly to other thunderstorms. First, moist, warmer air is lifted and surrounded by cooler air. The warmth of the “warmer” air is relative in this case because temperatures are still at or below freezing for snow to occur. This milder, rising air forms a cumulonimbus cloud from which precipitation falls. In this case, snow falls instead of rain. The cumulonimbus cloud is lower during thundersnow than normal thunderstorms, making thundersnow less intense.

What to expect when you’re expecting thundersnow

Thundersnow events often occur during blizzards. Snowfall rates of 2-4 inches are common during these storms, and the snow typically falls rapidly. Snowfall is often accompanied by high winds. Even with minimal winds, visibilities average less than ¼ of a mile making travel treacherous. Lightning flashes followed by thunder that can only be heard for 2-3 miles from the lightning. The sound of the thunder doesn’t travel as great a distance as it does during normal thunderstorms because the snow muffles the sound.

Footage of thunder snowstorms

You may have to see (or hear, in this case) thundersnow in order to get a feel for how incredible this event is. Luckily, Winter Storm Nemo has provided ample opportunity for such footage during its path of dropping 24-36 inches of snow across the northeast. Below is a video captured by Christine Heeren in New York. Lightning flashes around the 15 second mark followed by a deep rumble of thunder.

Thundersnow during Blizzard, Nemo