Lookout Pass is one of the most heavily traveled passes in Montana. It is situated on the border between Montana and Idaho, and although the altitude is only 4,710 feet, this is one of the most treacherous roads in the state. The reason can be seen in the image, keeping in mind that this is the view before the storm is due to hit.
This is very dangerous driving conditions.
It’ll get worse. There is an alternate route, but it is much longer.