Heavy Rain in Flathead County, Montana

A COOP observer reported a 4 day precipitation total of 4.25 during this event which was the highest manual observation. Other total amounts include: 4.20 Bigfork 3.2 miles east-northeast, 4.08 Columbia Falls 7.7 miles south, 3.52 Kalispell 1.7 miles northwest, 3.23 Olney, 3.22 Ronan 4.1 miles northeast, 3.01 West Glacier and 2.50 Thompson Falls 9.3 miles northwest. Kintla Lake Rd. in Glacier National Park was closed for a period of time due to water over the road and caused a campground crew to be stranded.

A cold upper level trough originating from the Gulf of Alaska moved slowly from northwest Washington on the morning of June 16 to southeast Idaho by early June 18 and then moved to the Alberta and Saskatchewan border by June 19. Several spokes of energy rotated counter-clockwise around this trough ingesting subtropical moisture originating from the Gulf of Mexico and brought periods of heavy precipitation to western Montana, totaling from 1 to up to 6 inches along the Continental Divide. The snow levels fell as low as 3,000 feet with the intense precipitation while high elevation locations in Glacier National Park received a couple feet of snow.