MTN News- Most people in the mountain country are familiar with what an Inversion is and we run into quite a few of them around this time of year.

Inversions are more typical for the valleys across Montana in the winter time.  What is an inversion? It is when a layer of cold air gets trapped at the surface and a layer of warmer air sits on top of it.

Story continues below

“Inversions sometimes can be very shallow.  You can have just a couple hundred feet and have a difference of 20 to 30 degrees within a couple of hundred feet.” said Ben Schott, NWS meteorologist.

Inversions are frequent and can be persistent. Many last for days and inversions only move when the weather gets windy.

“You need very strong winds to come in and help kind of push that cold dense air that is wanting to sink to the bottom of the valley floors, push that out of the area.” said meteorologist, Schott.


Winds mix the layers of warm and cold air together which can boost temperatures at the surface in a matter of minutes.  Even though inversions can occur practically anywhere, they are most common in valley which is why many valleys stay cold, and can have poor air quality in the winter months.

“When you see that smoke come up and then it kind of flattens out, you realize that there is something going on at that point.” said Ben Schott.

So the next time winds are in the forecast, valley dwellers should be glad as it brings warmer and cleaner air to the surface!