A cold Canadian system converged with a warm Pacific weather system to produced accumulating snow accross western Montana. Snow amounts ranged from eight to eighteen inches of new snow.
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 cold Canadian system converged with a warm Pacific weather system to produced accumulating snow accross western Montana. Snow amounts ranged from eight to eighteen inches of new snow. In addition, as the strong cold front pushed through northwest Montana, northeast winds caused blowing and drifting snow and low visibilities.
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 Dec 11, 2:58 AM PST, 7 hours 2 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.
A trained spotter in Elk City reported 14 inches of snow. The Idaho DOT reported 12 to 16 inches of new snow along Highway 12 between Lowell and Powell.
The Idaho DOT reported 14 inches of snow in Kooskia. A spotter in Weippe reported 12 inches of new snow.
The Hemlock Butte SNOTEL reported 8 inches of snow. A spotter in Pierce reported 10 inches of new snow.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2009Every state in 2009This day in weather historyWarnings in Idaho, December 2009
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 2026-09-30. Each event’s entry at NCEI: 206698, 206699, 206697.