A moist energetic Pacific storm system began to impact the northern Rockies Sunday afternoon and continued into Monday. The heaviest snowfall was across the mountains, but some valley locations picked up significant snowfall as the surface low pressure moved across western Montana.
Every event with a place to put it; 10 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 moist energetic Pacific storm system began to impact the northern Rockies Sunday afternoon and continued into Monday. The heaviest snowfall was across the mountains, but some valley locations picked up significant snowfall as the surface low pressure moved across western Montana.
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 Feb 6, 2:44 PM MST, 1 hour 16 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
244 PM MST SUN FEB 6 2011
...ANOTHER ROUND OF WINTRY WEATHER ON TAP...
.DISCUSSION...UNSETTLE NORTHWEST FLOW WILL SUPPORT OFF AND ON SNOW
SHOWERS OVER THE MOUNTAINS AND HIGHER ELEVATION VALLEYS SUCH AS
BUTTE THROUGH THE REMAINDER OF THE AFTERNOON AND EARLY EVENING.
THE FOCUS QUICKLY SHIFTS TO A PACIFIC LOW PRESSURE SYSTEM DIVING
INTO THE NORTHERN ROCKIES FROM BRITISH COLUMBIA BEGINNING THIS
EVENING. A DECENT FETCH OF SUBTROPICAL MOISTURE IS ASSOCIATED WITH
THE LOW... WHICH WILL SUPPORT LIGHT TO MODERATE LIQUID
PRECIPITATION AMOUNTS THROUGHOUT THIS WEATHER IMPACT EVENT.
ALTHOUGH FEW CHANGES WERE NECESSARY TO THE ONGOING FORECAST...THE
MESSAGE REMAINS THE SAME. SNOW WILL DEVELOP LATE THIS AFTERNOON
AND CONTINUE THROUGH MONDAY EVENING...FOLLOWED BY ARCTIC AIR
SPILLING OVER THE CONTINENTAL DIVIDE BEGINNING MONDAY MORNING.
AS SNOW DEVELOPS LATE THIS AFTERNOON...THE MOUNTAINS OF NORTH
CENTRAL IDAHO AND WESTERN MONTANA WILL RECEIVED THE BULK OF
PRECIPITATION DUE TO FAVORED UPSLOPE FLOW. SNOWFALL RATES MAY
BECOME MODERATE TO HEAVY AT TIMES OVERNIGHT THROUGH EARLY MONDAY
AFTERNOON...ESPECIALLY OVER MOUNTAIN PASSES. INCREASING SOUTHWEST
WINDS OVERNIGHT (MORE DETAILS BELOW) SHOULD KEEP NORTH CENTRAL
IDAHO AND SOUTHWEST MONTANA VALLEYS WELL-MIXED TONIGHT...
SUPPORTING EITHER RAIN OR A RAIN/SNOW MIX BEFORE AN INTRUDING
ARCTIC AIR MASS COOLS TEMPERATURES ENOUGH TO SUPPORT ALL SNOW.
LIGHT SNOW ACCUMULATIONS CAN BE EXPECTED ONCE THIS CHANGE-OVER
OCCURS DURING THE DAY MONDAY.
AS THE SURFACE LOW SLIDES INTO WESTERN MONTANA OVERNIGHT AND
DEEPENS...THE SURFACE PRESSURE GRADIENT WILL TIGHTEN...ESSENTIALLY
FROM THE I-90 CORRIDOR IN WEST CENTRAL MONTANA TO POINTS SOUTH
INTO SOUTHWEST MONTANA AND NORTH CENTRAL IDAHO. THE GRANGEVILLE
AREA WILL SEE SOUTH WINDS INCREASE LATE THIS EVENING WITH STRONG
GUSTS EXPECTED AFTER MIDNIGHT...DIMINISHING BY EARLY MONDAY
AFTERNOON. IN THE BITTERROOT VALLEY AND ALONG THE I-90 CORRIDOR
FROM ANACONDA TO DEER LODGE...SOUTHWEST WINDS WILL INCREASE
OVERNIGHT WITH STRONG GUSTS EXPECTED EARLY MONDAY MORNING...
DIMINISHING EARLY MONDAY AFTERNOON. WIND HIGHLIGHTS HAVE BEEN
ISSUED FOR THE GRANGEVILLE AND BUTTE REGIONS.
AS ARCTIC AIR BEGINS TO SPILL THROUGH THE GAPS OF THE CONTINENTAL
DIVIDE MONDAY MORNING...NORTHWEST MONTANA WILL LIKELY EXPERIENCE
BLOWING AND DRIFTING OF SNOW WHICH WILL CREATE LOCAL WHITEOUT
CONDITIONS AT TIMES...ESPECIALLY ALONG HIGHWAY 2 FROM COLUMBIA
FALLS TO MARIAS PASS. THE ARCTIC AIR IS EXPECTED TO INFILTRATE
WEST CENTRAL AND SOUTHWEST MONTANA MONDAY AFTERNOON. AS THE
COLDER/MORE DENSE ARCTIC AIR MASS FORCES THE WARMER/MORE MOIST
PACIFIC AIR OVER TOP OF IT...SNOWFALL NEAR THE CONTINENTAL DIVIDE
IS EXPECTED TO INTENSIFY AND BECOME MODERATE TO HEAVY AT TIMES.
GUSTY EAST WINDS WILL ALSO DEVELOP AND COULD PRODUCE LOCAL
WHITEOUT CONDITIONS AT TIMES DUE TO BLOWING SNOW...PRIMARILY NORTH
OF HIGHWAY 12 IN THE BLACKFOOT REGION...ALONG THE HIGHWAY 200
CORRIDOR FROM BONNER THROUGH OVANDO...AND THROUGH HELLGATE CANYON
INTO DOWNTOWN MISSOULA. TRAVELERS SHOULD ANTICIPATE HAZARDOUS
DRIVING CONDITIONS THROUGHOUT THE NORTHERN ROCKIES REGION
TONIGHT THROUGH MONDAY EVENING. SEVERAL WINTER HIGHLIGHTS HAVE
BEEN ISSUED. PLEASE REFER TO WWW.WEATHER.GOV/MISSOULA FOR THE MOST
CURRENT WEATHER INFORMATION AND UPDATES.
MONDAY NIGHT...THE UPPER LEVEL TROUGH OF LOW PRESSURE WILL BE
SAGGING SOUTH INTO THE GREAT BASIN REGION. ARCTIC AIR WILL
CONTINUE TO SPILL ACROSS THE DIVIDE INTO WESTERN MONTANA...WITH
SNOW TAPERING OFF ESPECIALLY ACROSS NORTHWEST MONTANA. THE BEST
CHANCES OF SNOW WILL HAVE SHIFTED OVER THE IDAHO PANHANDLE FOR
ADDITIONAL LIGHT ACCUMULATIONS THERE. THE COMBINATION OF VERY COLD
AIR AND WINDS WILL CREATE DANGEROUS WIND CHILL VALUES ALONG THE
CONTINENTAL DIVIDE.
TUESDAY...A NORTHERLY FLOW ALOFT WILL MAINTAIN THE COOL INFLUX
FROM CANADA. HOWEVER...THE SURFACE PRESSURE GRADIENT WILL BE
RELAXING AND WINDS ARE EXPECTED TO DIMINISH DURING THIS PERIOD.
WHILE SOME CLOUDS AND SNOW FLURRIES MAY LINGER OVER THE CLEARWATER
MOUNTAINS OF NORTH-CENTRAL IDAHO...MUCH OF WESTERN MONTANA WILL
SEE DRIER...BUT STILL COLD AIR.
TUESDAY NIGHT AND WEDNESDAY...FORECAST MODELS MAINTAIN A HIGH
AMPLITUDE RIDGE OF HIGH PRESSURE OVER THE EASTERN PACIFIC. SOME
MOISTURE WILL MAKE ITS WAY OVER THE TOP OF THE RIDGE AND INTO
WESTERN MONTANA. THE TEMPERATURE/MOISTURE PROFILE OF THE LOWER
ATMOSPHERE SHOWS THE POTENTIAL FOR LIGHT ACCUMULATIONS OF
CHAMPAGNE POWDER SNOW...WITH SNOW RATIOS IN THE 40-50:1 RANGE.
TEMPERATURES WILL BE MODERATING SLOWLY...BUT WILL REMAIN BELOW
SEASONAL AVERAGES FOR THIS TIME OF YEAR.
LONGEST RANGE FORECAST MODELS ARE BEGINNING TO SHOW SOME AGREEMENT
WITH REGARD TO AN OVERALL PATTERN CHANGE ACROSS NORTH AMERICA
EXPECTED TO OCCUR NEXT WEEKEND. THE BIGGEST QUESTIONS WHICH
REMAIN ARE HOW QUICKLY WILL THIS CHANGE OCCUR AS WELL AS HOW MUCH
WARMING WILL THE NORTHERN ROCKIES EXPERIENCE AS THE RIDGE MOVES
OVER THE AREA AND A TROUGH BEGINS TO DEEPEN OVER THE PACIFIC
COAST. AT THIS TIME HAVE MAINTAINED A RATHER CONSERVATIVE FORECAST
KEEPING CHANCES FOR PRECIPITATION ACROSS NORTHWEST MONTANA...
GLACIER NATIONAL PARK (GNP) AND THE SEELEY/SWAN REGION ON THURSDAY
AND ONLY SLIGHTLY FARTHER TO THE SOUTH ON FRIDAY. THERE IS MUCH
BETTER MODEL AGREEMENT THAT THE MAIN WEATHER SYSTEM WILL MOVE
INLAND OVER THE WEEKEND. THUS HAVE RAISED CHANCES FOR
PRECIPITATION SIGNIFICANTLY...ESPECIALLY OVER THE MOUNTAINS...
NORTHWEST MONTANA...GNP AND THE SEELEY/SWAN REGION. TEMPERATURES
WILL WARM ON THURSDAY AND LIKELY BE ABOVE NORMAL BY FRIDAY IN SOME
LOCATIONS. HOWEVER...CONDITIONS WILL COOL OVER THE WEEKEND BACK
TOWARDS NORMAL.
&&
.AVIATION...LIGHT SNOW IS FORECAST TO BEGIN TO AFFECT KGPI WITH
REDUCTIONS IN VISIBILITY AND CLOUDS LOWERING AFTER 07/0000Z. THE
HEAVIEST SNOWFALL SHOULD OCCUR DURING THE MORNING HOURS ON MONDAY
BEFORE WINDS SWITCH TO THE NORTHEAST AND BECOME GUSTY AFTER
07/1800Z AS THE ARCTIC FRONT APPROACHES. VICINITY SNOW SHOWERS
PRESENTLY AROUND KMSO WILL INCREASE THIS EVENING AND COULD RESULT
IN SOME IMPACTS TO THE AIRFIELD. HOWEVER...BY EARLY MONDAY MORNING
GUSTY WINDS ARE FORECAST AT KMSO WHICH SHOULD LIMIT SNOW SHOWERS
TO THE VICINITY MOUNTAINS. LATER IN THE AFTERNOON...SNOW SHOWERS
WILL RETURN TO KMSO BRINGING ANOTHER ROUND OF POTENTIAL IMPACTS TO
AVIATION. KBTM WILL CONTINUE TO SEE VICINITY SNOW SHOWERS WHICH
MAY RESULT IN BRIEF BUT FAIRLY DRAMATIC REDUCTIONS IN VISIBILITY
THROUGH THIS EVENING AND POTENTIALLY OVERNIGHT. GUSTY WINDS ARE
ALSO FORECAST TO IMPACT THE AIRFIELD MONDAY MORNING. PERIODIC SNOW
SHOWERS ARE FORECAST FOR THE VICINITY OF KSMN THIS EVENING WITH
SOME POTENTIALLY AFFECTING THE AIRFIELD WITH REDUCTIONS IN
VISIBILITY AND LOWERED CLOUDS. MONDAY MORNING WILL ALSO BRING
GUSTY WINDS TO KSMN...WHICH SHOULD LIMIT SNOW SHOWERS TO THE
MOUNTAINS.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT... WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 PM MST
MONDAY KOOTENAI/CABINET REGION...LOWER CLARK FORK REGION.
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 5 PM MST MONDAY
FOR THE FLATHEAD VALLEY.
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 5 PM MST MONDAY
WEST GLACIER REGION.
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 11 PM MST
MONDAY BITTERROOT/SAPPHIRE MOUNTAINS.
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 11 PM MST
MONDAY POTOMAC/SEELEY LAKE REGION.
WINTER WEATHER ADVISORY FROM 11 AM TO 11 PM MST MONDAY
BUTTE/BLACKFOOT REGION.
WIND ADVISORY FROM 2 AM TO 11 AM MST MONDAY BUTTE/BLACKFOOT
REGION.
ID...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 10 PM PST
MONDAY ABOVE 3000 FEET FOR THE NORTHERN CLEARWATER
MOUNTAINS...SOUTHERN CLEARWATER MOUNTAINS.
WIND ADVISORY FROM 10 PM THIS EVENING TO 10 AM PST MONDAY FOR
GRANGEVILLE AND VICINITY.
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 11 PM MST
MONDAY EASTERN LEMHI COUNTY.
&&
SHORT TERM...DEROSA/MSJ
LONG TERM....MSJ/DICKERSON
AVIATION...DICKERSONThe national radar mosaic for the moment the first event began.
7 winter storm, 3 heavy snow. Local standard time, as filed.
A trained spotter 1 miles south of Condon reported 11 inches of snow over 24 hours.
A report from the public 10 miles north of Seeley lake, estimated 15 inches of snow.
Total snowfall at Missoula International airport was 12.4 inches, with 5 inches falling from 5pm to 7pm on the 7th.
Snowfall in the University district for the 24 hour period was measured at 11 inches. During that time 3 inches fell in 1 hour.
A trained spotter in Bigfork reported 6 inches of snow.
The equipment at Glacier Park International Airport reported northeast winds between 18 to 22 mph from 1pm until 10 pm, along with gusts to 36 mph at 2pm. The fire hall measured 5 inches of snow.
Over Marias Pass the department of highways reported 8 inches of snowfall.
Severe driving conditions were reported throughout the city of Missoula and Missoula county, including highway 93 from Missoula south to Lolo.
Heavy snow was reported northeast of Essex, with 9 inches measured.
Severe driving conditions were reported on US-12 from Avon to MacDonald Pass. Chains were required for all towing units. Road conditions were snowpacked and icy, along with snow falling with blowing and drifting snow, resulted in reduced visibilities.
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, February 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 2026-09-24. Each event’s entry at NCEI: 279749, 279752, 279754, 279755, 279751, 279753, 279748, 279756, 279747, 279750.