This rain reminds me of my backpacking trips here in the 70's. Glad I'm in a cabin but feel bad for the backcountry folks.
Drove to great falls today to get out of the weather. Visited the L&C any Charlie Russell museums. Drove back to completely socked in moisture. Supposed to be another day of it.
Almost went up to Glacier this weekend and glad we changed our plans. I had 4 days off and instead headed up to Kelly Creek flyfishing. Thursday night we had thunderstorms for 8 hrs continuously and yesterday afternoon got a major hail storm on the way home. The area is in the Bitteroots, close to the Montana border. The storms were heading up to Glacier and probably made for some miserable camping. The webcams show the East side pretty wet.
I was there for the famous August of 1992 snow storm that left about 17 inches of snow and closed down the park for a couple of days, so it can happen. Actually the weather here today is perfect and I think it is heading your way.