Moisture streamed into the region from the Pacific Ocean as a large weather system moved out of British Columbia with an associated jet streak, producing large scale lift and gusty winds. At the same time, a very cold arctic air mass moved into northwest Montana out of Alberta.
Every event with a place to put it; 6 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.
Moisture streamed into the region from the Pacific Ocean as a large weather system moved out of British Columbia with an associated jet streak, producing large scale lift and gusty winds. At the same time, a very cold arctic air mass moved into northwest Montana out of Alberta.
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 Jan 29, 8:04 AM MST, 2 hours 56 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
804 AM MST SAT JAN 29 2011
.UPDATE...ADDED PATCHY FREEZING DRIZZLE TO PORTIONS OF NORTHWEST
MONTANA THIS MORNING.
&&
.DISCUSSION...LIGHT CONVECTIVE PRECIPITATION MOVING ACROSS THE
NORTHERN ROCKIES HAS USHERED A WARMER PACIFIC AIR MASS OVER COOLER
VALLEY TEMPERATURES IN PORTIONS OF NORTHWEST MONTANA THIS MORNING.
THIS IS PRODUCING PATCHES OF FREEZING DRIZZLE AS CONFIRMED BY A
RECENT SPOTTER REPORT. SUB-SURFACE TEMPERATURES ARE SITTING AT OR
JUST BELOW FREEZING WHICH COULD CREATE SLICK ROAD CONDITIONS AT
TIMES THROUGH THE MORNING.
&&
.AVIATION...PATCHY FREEZING DRIZZLE IN NORTHWEST MONTANA MAY
CREATE AVIATION CONCERNS DUE TO ICING...HOWEVER THERE SHOULD BE NO
IMPACT TO KGPI OPERATIONS. A PACIFIC WEATHER SYSTEM WILL OVERRIDE AN
INTRUDING ARCTIC BOUNDARY BEGINNING NEAR KGPI THIS AFTERNOON. THIS
COULD CAUSE BLOWING SNOW AND GREATLY REDUCED VISIBILITIES FOR
SEVERAL HOURS. THE BOUNDARY WILL PUSH INTO THE KMSO AND KBTM AREAS
EARLY SUNDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 338 AM MST SAT JAN 29 2011/
DISCUSSION...
TODAY...MOISTURE STREAMING IN OFF THE PACIFIC OCEAN WILL COMBINE
WITH A WEATHER SYSTEM DIGGING OUT OF BRITISH COLUMBIA. THE FOCUS
OF PRECIPITATION WILL BE DIRECTED ACROSS THE IDAHO PANHANDLE AND
INTO NORTHWEST MONTANA THANKS TO LARGE-SCALE LIFT OFFERED BY A
PASSING JET STREAK IN THE VICINITY. AN ARCTIC AIR MASS HAS BEEN
ADVANCING SOUTHWARD ACROSS ALBERTA THIS MORNING...AND WILL BE
PUSHING INTO MONTANA TODAY. EVENTUALLY...THE BUILDUP OF COLD AIR
WILL SURGE ACROSS THE CONTINENTAL DIVIDE...STARTING FIRST IN THE
GLACIER PARK REGION LATER THIS AFTERNOON.
TONIGHT AND SUNDAY...THE COMBINATION OF RELATIVELY WARM MOIST
PACIFIC AIR MOVING IN FROM THE WEST CLASHING WITH THE SURGING
ARCTIC AIR MASS FROM CENTRAL CANADA WILL CREATE SOME NASTY WINTER
WEATHER CONDITIONS ACROSS WESTERN MONTANA AND THE IDAHO PANHANDLE.
AS SNOWFALL AND NORTHEAST WINDS INCREASE...LOCAL BLIZZARD
CONDITIONS ARE POSSIBLE IN THE WEST GLACIER REGION AND THE
NORTHERN FLATHEAD VALLEY. THE ARCTIC SURGE WILL EVENTUALLY MAKE
ITS WAY INTO WEST-CENTRAL MONTANA...INCLUDING THE MISSOULA VALLEY
BY EARLY SUNDAY MORNING. GET READY FOR SOME ACCUMULATING SNOW...
BLOWING AND DRIFTING OF SNOW...AND BONE-CHILLING TEMPERATURES AS
THIS WINTER EVENT UNFOLDS. SEVERAL WINTER WARNINGS AND ADVISORIES
HAVE BEEN ISSUED TO HIGHLIGHT THIS WINTER STORM. EXPECT
TEMPERATURES TO HOLDING STEADY OR SLOWLY FALLING THROUGHOUT THE
DAY SUNDAY AS COLD AIR SURGES ACROSS WESTERN MONTANA INTO NORTH-
CENTRAL IDAHO.
SUNDAY NIGHT...THE UPPER TROUGH AND THE VERY COLD AIR MASS
ASSOCIATED WITH IT WILL BE MOVING DIRECTLY OVER THE NORTHERN
ROCKIES REGION DURING THIS PERIOD. THE AIR MASS WILL UNDERGO
DRYING AS EVEN COLDER AIR PUSHES SOUTH OUT OF CANADA. WHILE LIGHT
ACCUMULATING SNOW CAN STILL BE EXPECTED ACROSS IDAHO AND
CLEARWATER COUNTIES (IN NORTH-CENTRAL IDAHO)...WESTERN MONTANA
WILL BE DEALING WITH THE EFFECTS OF BOTH WINDS AND BITTERLY COLD
TEMPERATURES. EXPECT TO SEE WIND CHILL VALUES IN THE 15 BELOW TO
25 BELOW ZERO RANGE ACROSS NORTHWEST MONTANA AND THROUGH THE GAPS
OF THE CONTINENTAL DIVIDE.
MONDAY THROUGH FRIDAY...A RIDGE BUILDS ALONG THE WEST COAST
PRODUCING A NORTH TO NORTHEAST FLOW INTO THE REGION. THIS WILL HELP
TO BRING IN MORE COLD AIR TO REINFORCE THE ARCTIC AIR THAT MOVED IN
OVER THE WEEKEND. AS THE SKIES CLEAR OVERNIGHT...TUESDAY MORNING
LOOKS TO BE THE COLDEST WITH A VERY SLOW WARMING TREND FOR THE REST
OF THE WEEK. THE DRY NORTH TO NORTHEAST FLOW WILL BE TOO DRY TO SEE
ANY PRECIPITATION OVER WESTERN MONTANA AND NORTH CENTRAL IDAHO.
HOWEVER...THERE COULD BE ENOUGH MOISTURE NEAR THE GROUND TO CAUSE
SOME FOG AND LOW STRATUS.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY FROM 5 AM TO 11 PM MST SUNDAY
MISSOULA/BITTERROOT VALLEYS.
WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 5 PM MST
SUNDAY LOWER CLARK FORK REGION.
WINTER STORM WARNING FROM 2 PM THIS AFTERNOON TO 5 PM MST SUNDAY
FLATHEAD/MISSION VALLEYS.
WINTER STORM WARNING FROM 11 AM THIS MORNING TO 5 PM MST SUNDAY
WEST GLACIER REGION.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 11 AM MST
SUNDAY KOOTENAI/CABINET REGION.
WINTER WEATHER ADVISORY FROM 5 AM TO 11 PM MST SUNDAY
BITTERROOT/SAPPHIRE MOUNTAINS.
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 5 PM MST SUNDAY
POTOMAC/SEELEY LAKE REGION.
WINTER WEATHER ADVISORY FROM 5 AM TO 11 PM MST SUNDAY
BUTTE/BLACKFOOT REGION.
ID...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 10 PM PST
SUNDAY NORTHERN CLEARWATER MOUNTAINS.
WINTER WEATHER ADVISORY FROM 4 AM TO 10 PM PST SUNDAY ABOVE 3000
FEET FOR THE SOUTHERN CLEARWATER MOUNTAINS.
&&
UPDATE...DEROSA
PREVIOUS DISCUSSION...MSJ/KOLATA
AVIATION...DEROSAThe national radar mosaic for the moment the first event began.
3 winter storm, 3 heavy snow. Local standard time, as filed.
Montana Department of Transportation reported 6 to 8 inches of snow along Highway 2 from Essex to 7 miles west of Marias Pass.
Heavy snow was reported around Columbia Falls. A spotter measured 13 inches of snow 1 mile southwest of Columbia Falls. Another spotter reported 10 inches of snow with wind gust to 50 mph. This produced near whiteout conditions and large snow drifts. Several tree limbs up to 6 inches in diameter were broken off.
Snowfall was estimated at 7 inches, 2 miles west-southwest of Yaak and 6 inches 8 miles North of Eureka.
Heavy snow was reported around Condon with 6 inches measured 8 miles south of Condon and 7 inches in Condon.
Sustained winds of over 30 mph with gusts over 40 mph,along with periods of heavy snow, produced areas of blowing and drifting snow and very low visibilities at the Glacier Park International Airport.
Near Potomac the public measured 7 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, January 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: 275875, 275878, 275885, 275883, 275880, 275884.