I have seen them a few times here in Montana. I have a friend who is a photographer from my home town who has a few photos of them. They are definitely not as prominent here as they are there, but still amazing to see. Here is a link to one of my friends photos...

https://www.facebook.com/ridlephoto/photos/a.139351816115775.36740.134221206628836/1598199786897630/?type=3&theater