Pacific moisture continued to stream into the northern Rockies under a westerly flow aloft.
Every event with a place to put it; 1 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.
Pacific moisture continued to stream into the northern Rockies under a westerly flow aloft.
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 1, 7:05 PM MST, 5 hours earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
705 PM MST WED DEC 1 2010
.DISCUSSION...FORECAST IS STILL GENERALLY ON TRACK FROM THE MID
AFTERNOON DISCUSSION...BUT DID MAKE A FEW ALTERATIONS TO THE
WINTER WEATHER ADVISORY. THE LOWER VALLEYS OF IDAHO ARE EXPECTED
TO SEE MAINLY RAIN UNTIL SNOW LEVELS DROP BEHIND THE COLD FRONT
THURSDAY NIGHT. THEREFORE HAVE REDEFINED THE ADVISORY IN THAT AREA
TO ABOVE 2000 FEET. ALSO ADDED A WINTER WEATHER ADVISORY FOR
MODERATE ACCUMULATIONS IN LEMHI COUNTY THURSDAY AND THURSDAY
NIGHT. THE GREATEST ACCUMULATIONS IN THAT REGION WILL LIKELY BE
FROM GIBBONSVILLE TO LOST TRAIL PASS...BUT THE VALLEYS WILL BE
IMPACTED AS WELL.
&&
.AVIATION...
A BRIEF PERIOD OF INCREASED CEILING HEIGHTS WILL QUICKLY END BY
THIS EVENING AS CLOUD COVER BEGINS TO ENTER THE REGION. LOWERED
CEILING AND WIDESPREAD SNOW WILL BEGIN AROUND 03Z THIS EVENING IN
IDAHO. THIS SNOW WILL THEN MOVE EASTWARD WITH MOST AIRFIELDS
SEEING LOW CEILING AND VISIBILITY BY THURSDAY MORNING. A SHORTWAVE
PASSAGE WILL CAUSE AN INCREASE IN SNOW BY THURSDAY AFTERNOON FROM
KMSO SOUTHWARD THAT WILL LIKELY LAST INTO THE OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 247 PM MST WED DEC 1 2010/
DISCUSSION...
TONIGHT/THURSDAY...PACIFIC MOISTURE CONTINUES TO STREAM INTO THE
NORTHERN ROCKIES REGION UNDER WESTERLY FLOW ALOFT TONIGHT. VALLEY
TEMPERATURES HAVE WARMED INTO THE 30S ACROSS MUCH OF THE AREA...
EVEN SOME LOWER 40S ACROSS CLEARWATER AND IDAHO COUNTIES THIS
AFTERNOON. WARMER NEAR THE SURFACE TONIGHT AND AGAIN ON THURSDAY
WILL LIKELY LIMIT SNOW ACCUMULATIONS DUE TO VARYING DEGREES OF
MELTING...WHICH WILL BE ESPECIALLY TRUE ON THURSDAY. ON THE OTHER
HAND...HIGHER TERRAIN WILL LIKELY SEE ADDITIONAL SNOW ACCUMULATION
IMPACTING TRAVEL OVER THE PASSES ALONG THE IDAHO/MONTANA BORDER. A
SURFACE LOW IS EXPECTED TO TREK ACROSS CENTRAL IDAHO/WEST-CENTRAL
MONTANA THURSDAY. THE TRACK OF THIS LOW WILL HOLD THE KEY TO WHEN
THE SNOW BEGINS AND HOW MUCH SNOW LOCATIONS LIKE THE
MISSOULA/BITTERROOT VALLEYS.
THURSDAY NIGHT...THE MAIN UPPER TROUGH AND ASSOCIATED COLD FRONT
WILL PASS THROUGH THE NORTHERN ROCKIES REGION. IT WILL BE DURING
THIS PERIOD WHERE WEST-CENTRAL MONTANA VALLEYS WILL SEE THE BEST
OPPORTUNITY FOR ACCUMULATING SNOW...WITH A QUICK SHOT OF LOCALLY
HEAVY SNOW WITH THE FRONT. WINTER WEATHER ADVISORIES HAVE BEEN
ISSUED TO ADDRESS SNOW CONCERNS...SEE BELOW.
FRIDAY...COLDER AIR WILL BE MOVING INTO THE REGION WITH THE
PASSAGE OF THE FRONTAL SYSTEM. PRECIPITATION WILL BECOME SHOWERY
AND MORE CONFINED TO THE MOUNTAINS. BREEZY WEST TO NORTHWEST WINDS
CAN BE EXPECTED IN THE AFTERNOON.
SATURDAY THROUGH WEDNESDAY...NO CHANGES MADE TO THE FORECAST
DURING THIS PERIOD.
AVIATION...
A BRIEF PERIOD OF INCREASED CEILING HEIGHTS WILL QUICKLY END BY
THIS EVENING AS CLOUD COVER BEGINS TO ENTER THE REGION. LOWERED
CEILING AND WIDESPREAD SNOW WILL BEGIN AROUND 03Z THIS EVENING IN
IDAHO. THIS SNOW WILL THEN MOVE EASTWARD WITH MOST AIRFIELDS
SEEING LOW CEILING AND VISIBILITY BY THURSDAY MORNING. A SHORTWAVE
PASSAGE WILL CAUSE AN INCREASE IN SNOW BY THURSDAY AFTERNOON FROM
KMSO SOUTHWARD THAT WILL LIKELY LAST INTO THE OVERNIGHT.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY FROM 5 AM THURSDAY TO 5 AM MST FRIDAY
BITTERROOT/SAPPHIRE MOUNTAINS...LOWER CLARK FORK REGION.
WINTER WEATHER ADVISORY FROM 11 AM THURSDAY TO 5 AM MST FRIDAY
POTOMAC/SEELEY LAKE REGION.
WINTER WEATHER ADVISORY FROM 11 AM THURSDAY TO 5 AM MST FRIDAY
BUTTE/BLACKFOOT REGION.
WINTER WEATHER ADVISORY FROM 2 PM THURSDAY TO 5 AM MST FRIDAY
MISSOULA/BITTERROOT VALLEYS.
ID...WINTER WEATHER ADVISORY FROM 5 AM THURSDAY TO 5 AM MST FRIDAY
EASTERN LEMHI COUNTY...WESTERN LEMHI COUNTY.
WINTER WEATHER ADVISORY FROM 1 AM THURSDAY TO 4 AM PST FRIDAY
FOR WHITE BIRD GRADE.
WINTER WEATHER ADVISORY FROM 1 AM THURSDAY TO 4 AM PST FRIDAY
ABOVE 2000 FEET FOR THE OROFINO/GRANGEVILLE REGION.
WINTER WEATHER ADVISORY UNTIL 4 AM PST FRIDAY NORTHERN
CLEARWATER MOUNTAINS...SOUTHERN CLEARWATER MOUNTAINS.
&&
UPDATE...WHITMORE/DICKERSON
PREVIOUS...MSJ/ZUMPFE/KITSMILLERHAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE MISSOULA MT 1015 AM MST WED DEC 1 2010 MTZ004-021200- LOWER CLARK FORK REGION- 1015 AM MST WED DEC 1 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WEST CENTRAL MONTANA. FOR THE LATEST INFORMATION ON WATCHES...WARNINGS AND ADVISORIES...GO TO WEATHER.GOV/MISSOULA. .DAY ONE...TODAY AND TONIGHT THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER FOR TODAY IS LOW. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY ANOTHER PACIFIC WEATHER SYSTEM WILL SPREAD SNOW ACROSS THE LOWER CLARK FORK REGION THURSDAY THROUGH THURSDAY NIGHT. ANOTHER ROUND OF MODERATE ACCUMULATIONS IN THE VALLEYS AND THE MOUNTAINS IS POSSIBLE. THIS EVENT WILL HAVE LESS WIND WITH IT BEING A MORE STEADY SNOW EVENT. NEVERTHELESS...IT WILL LIKELY HAVE AN IMPACT ON TRAVEL. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. IDZ006-MTZ006-043-021200- SOUTHERN CLEARWATER MOUNTAINS-BITTERROOT/SAPPHIRE MOUNTAINS- POTOMAC/SEELEY LAKE REGION- 1015 AM MST WED DEC 1 2010 /212 AM PST WED DEC 1 2010/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL IDAHO AND WEST CENTRAL MONTANA. .DAY ONE...TODAY AND TONIGHT THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER FOR TODAY IS LOW. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY ANOTHER PACIFIC WEATHER SYSTEM WILL SPREAD SNOW ACROSS THE NORTH CENTRAL IDAHO AND WEST CENTRAL MONTANA THURSDAY THROUGH THURSDAY NIGHT. ANOTHER ROUND OF MODERATE ACCUMULATIONS IN THE VALLEYS AND THE MOUNTAINS IS POSSIBLE. THIS EVENT WILL HAVE LESS WIND WITH IT BEING A MORE STEADY SNOW EVENT. NEVERTHELESS...IT WILL LIKELY HAVE AN IMPACT ON TRAVEL. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. IDZ005-007-021200- NORTHERN CLEARWATER MOUNTAINS-OROFINO/GRANGEVILLE REGION- 1015 AM PST WED DEC 1 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL IDAHO. FOR THE LATEST INFORMATION ON WATCHES...WARNINGS AND ADVISORIES...GO TO WEATHER.GOV/MISSOULA. .DAY ONE...TODAY AND TONIGHT PERSISTENT LIGHT SNOW AND LOCALLY BREEZY WINDS WILL CONTINUE THROUGH EARLY MORNING. THIS WILL IMPACT TRAVEL IN THE HIGHWAY 11 AND HIGHWAY 12 CORRIDORS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY ANOTHER PACIFIC WEATHER SYSTEM WILL SPREAD SNOW ACROSS NORTH CENTRAL IDAHO THURSDAY THROUGH THURSDAY NIGHT. ANOTHER ROUND OF MODERATE ACCUMULATIONS IN THE VALLEYS AND THE MOUNTAINS IS POSSIBLE. THIS EVENT WILL HAVE LESS WIND WITH IT BEING A MORE STEADY SNOW EVENT. NEVERTHELESS...IT WILL LIKELY HAVE AN IMPACT ON TRAVEL. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. MTZ005-021200- MISSOULA/BITTERROOT VALLEYS- 1015 AM MST WED DEC 1 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WEST CENTRAL MONTANA. .DAY ONE...TODAY AND TONIGHT THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER FOR TODAY IS LOW. PLEASE SEE NEXT SECTION FOR A POTENTIAL WEATHER IMPACT. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY ANOTHER PACIFIC WEATHER SYSTEM WILL SPREAD SNOW ACROSS THE MISSOULA AND BITTERROOT VALLEYS THURSDAY THROUGH THURSDAY NIGHT. ANOTHER ROUND OF MODERATE ACCUMULATIONS IN THE VALLEYS AND THE MOUNTAINS IS POSSIBLE. THIS EVENT WILL HAVE LESS WIND WITH IT BEING A MORE STEADY SNOW EVENT. NEVERTHELESS...IT WILL LIKELY HAVE AN IMPACT ON TRAVEL. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
The national radar mosaic for the moment the first event began.
1 heavy snow. Local standard time, as filed.
Spotter reported 6 inches of snow in Grangeville.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2010Every state in 2010This day in weather historyWarnings in Idaho, December 2010
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 2026-09-24. Each event’s entry at NCEI: 272874.