We have driven from the Great Falls area to AZ often. The canyon between Great Falls and Helena CAN be treacherous. I lived at Exit 240 and drove into Cascade in the early morning hours to post office. So if you can drive thru there around noon on a bad snow day, do so. If you feel safer slowing down to 15 mph, do so. The worst scenario is being passed by trucks in lots of snow. Feels like you are in a blizzard. I always breath a sigh of relief after passing Billings ... going either way. Idaho Falls never bothered me compared to Montana. As previous ladies have said, check the weather forecast. Of course, Fred (TV Channel 5) is not always correct.
Following is the weather camera website located north of exit 240. It will give you an idea how the weather is in the canyon.
http://rwis.mdt.mt.gov/scanweb/SWFra...atus=&Camera=1
Living in Canada, you should be used to the snow.
