Spring storm brings rare thundersnow to Minnesota

The spring snowstorm moving through Minnesota has brought a mix of snow, sleet, rain and now thundersnow.

Viewer Michael Crouse captured this video of a lightning strike near Alexandria Thursday.

But what makes thundersnow such a rare event?

In order for thundersnow to occur, the right conditions need to be in place. There needs to be instability in the atmosphere for lightning to create lightning and thunder. To get instability, you typically need heat and moisture.

Think of the atmosphere like a pot of water on the stove. In order for something to boil in the pot, you need two fairly obvious ingredients: water and heat by turning on the stove. When the pot begins to boil, you can say that there is now instability.

The atmosphere works in a very similar way, except obviously in the case of thundersnow there can’t be a whole lot of heat because the freezing point is 32 degrees. Therefore, the entire atmosphere has to be below freezing to get snow to fall all the way to the ground.

So in order to get the instability needed for lightning, there needs to be a massive amount of moisture moving into an area at almost every layer of the atmosphere. This doesn’t happen all that often in the winter, especially in Minnesota. That’s why thundersnow is a fairly rare occurrence worldwide, and even more rare here in Minnesota.