A trough of low pressure moved out of the Pacific northwest and helped draw some tropical moisture into western Montana. The main impact of snowfall was over the higher terrain and mountain passes.
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS MSO wrote it up.
A trough of low pressure moved out of the Pacific northwest and helped draw some tropical moisture into western Montana. The main impact of snowfall was over the higher terrain and mountain passes.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Missoula, MT wrote its last area forecast discussion before the first event at Apr 17, 9:46 AM MST, 1 hour 46 minutes earlier.
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</html>The national radar mosaic for the moment the first event began.
3 heavy snow. Local standard time, as filed.
Montana Department of Transportation reported 24 inches of snow 12 miles eastnortheast of Essex Montana.
A spotter reported 12 inches of new snowfall around Essex.
US highway 2 from West Glacier to Essex recieved 6 inches of snow. |US highway 2 from Essex to 7 miles west of Marias pass received 12 inches of snow.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2011Every state in 2011This day in weather historyWarnings in Montana, April 2011
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 287813, 287814, 287816.