Thundersnow

Thundersnow?  Say what?  What the heck is that?  Well, it is thunder during a snow storm.  It doesn't happen as often as regular thunderstorms, but it DOES happen occasionally.  Because it is rather rare, and because we normally don't go camping in winter weather, it is unlikely you will encounter it during an outing.  But you might and it would be good to know what -- if anything --- to do when it happens.  One good thing about thundersnow, besides being rare, is that it usually doesn't last very long.   The meteorological conditions that create thunder don't usually occur in really cold weather.

Normal thunderstorms are the product of very tall, narrow columns of clouds.  Rising warm air and falling cool air create an increasingly powerful cycle of wind within the column.  Static electricity builds up between opposing currents in the cloud until it has sufficient charge to arc to the ground or to other clouds.  Winter usually doesn't produce the right kind of temperature differences to spawn thunderstorms but it can happen on occasion.  It isn't absolute temperatures but differences in temperature that can cause thunderstorms.

Normal snow storms usually come from wide, flat cloud systems so they don't usually generate lightning and thunder.  But occasionally rising warm air will disrupt the normal cloud formation and create bulges or tall columns capable of creating lightning and thunder and thundersnow is born.

I have personally only seen a thundersnow once or twice, even though I grew up in southern Idaho where we had some rather severe winters (-26°F at least once and one February where the high never got above -6°F for two weeks).  The first thundersnow I saw was on Christmas Eve in Salt Lake City a couple of years ago.  At first I thought the flashing of the lightning was just fluctuations in street lighting, but real thunder soon confirmed it was a rare thundersnow.  It was rather exciting and quite beautiful.  We experienced another brief bout this past winter in southern Utah County, a few miles south of Utah Lake. I suspect the proximity to reasonably large bodies of water may have had something to do with creating the temperature differences needed to generate thunder.

If you should get caught in a thundersnow in camp, you should take all the precautions you would for Camping In Snow and Camping In Thunderstorms.  You are very likely to encounter the potential risks -- and beauty -- of both.

Be safe!