WAVE 3 Weather
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I've had several calls, emails & facebook posts tonight about seeing lightning & hearing thunder. You're not crazy... that's what you saw and heard. A pretty rare event - thundersnow!
Here's a capture of the radar from Thursday evening - showing the lightning strikes like we'd typically see with a summer-time thunderstorm!
What causes Thundersnow?
Thundersnow — when thunder and lighting occur during a snowstorm— most often appears in late winter or early spring. That's because the ingredients for thundersnow—a mass of cold air on top of warm, plus moist air closer to the ground—often come together during that time.
Thundersnow starts out like a summer thunderstorm. The sun heats the ground and pushes masses of warm, moist air upward, creating unstable air columns. As it rises, the moisture condenses to form clouds, which are jostled by internal turbulence. The "tricky part" for making thundersnow, is creating that atmospheric instability in the wintertime. For thundersnow to occur, the air layer closer to the ground has to be warmer than the layers above, but still cold enough to create snow—a very precise circumstance. Snowfall rates during a thundersnow event can reach two inches an hour.
Remember this Thundersnow?
February 2, 2012 - Jim Cantore surprised by Thundersnow in Chicago.