Arctic high pressure brought a bitter airmass to the area. Winds then contributed to dangerous wind chills for much of the area for the third night in a row.
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 GGW wrote it up.
Arctic high pressure brought a bitter airmass to the area. Winds then contributed to dangerous wind chills for much of the area for the third night in a row.
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 Glasgow, MT wrote its last area forecast discussion before the first event at Feb 1, 5:23 PM MST, 37 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GLASGOW MT 523 PM MST TUE FEB 1 2011 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY... VERY COLD AIR HAS SETTLED INTO THE RIVER VALLEYS OF NORTHEAST MONTANA AS ARCTIC HIGH SLIDES TO THE SOUTH. WARMER AIR ALREADY MOVING IN ALOFT AS INDICATED BY THE ABOVE ZERO TEMPERATURES IN CENTRAL MONTANA BUT REMAINED AT -15 TO -20 IN THE VALLEYS. EXPECT SITUATION TO CONTINUE OVERNIGHT...WITH THE MILK/MISSOURI VALLEYS RETAINING THE COLD AIR. WINDS WILL REMAIN LIGHT FROM THE SOUTHEAST...WITH OCCASIONAL PUFFS TO DROP WIND CHILLS TO 40 BELOW OR MORE. FOR NOW WILL KEEP WIND CHILL ADVISORY GIVEN EXPECTED LIGHT WINDS...BUT MAY NEED UPDATED LATER TO A WARNING IF WINDS COME UP OR TEMPERATURES FALL MORE THAN EXPECTED. DO NOT EXPECT WIND CHILL ISSUES TO LAST PAST WEDNESDAY MORNING AS UPPER RIDGE FOLDS OVER INTO WESTERN CANADA SPREADING WARM AIR SOUTHWARD. EXPECT MOST AREAS TO SEE READING ABOVE ZERO BY WEDNESDAY AFTERNOON AND LIKELY NEAR OR ABOVE FREEZING BY THURSDAY. EXCEPTION WILL BE IN THE LOWER MILK/MISSOURI BASIN WHERE COLD AIR MAY BE DIFFICULT TO SCOUR OUT. .LONG TERM...THURSDAY NIGHT THROUGH TUESDAY... THE PERSISTENT UPPER RIDGE ALONG THE WEST COAST WILL KEEP NORTHWESTERLY FLOW ALOFT OVER NORTHEAST MONTANA THROUGHOUT THE EXTENDED PERIOD. AN EMBEDDED SHORT-WAVE DISTURBANCE IN THIS UPPER FLOW WILL SLIDE INTO WESTERN NORTH DAKOTA AND MINNESOTA THURSDAY NIGHT AND FRIDAY. THIS WAVE WILL NUDGE THE STATIONARY ARCTIC FRONT SOUTHWEST INTO THE FORECAST AREA. THE STATIONARY BOUNDARY MOVES FARTHER WEST FRIDAY NIGHT MEETING OVERRUNNING MOISTURE. THERE ARE DIFFERENCES BETWEEN ECMWF AND THE GFS WHERE THE BOUNDARY WILL BE...WHICH WILL DETERMINE WHERE ANY RESULTING MOISTURE FALLS. AVAILABLE QPF RANGES AROUND 0.05-0.10 INCH. SATURDAY THROUGH SUNDAY...A POLAR VORTEX OVER NORTHERN CANADA WILL ROTATE A WAVE AROUND ITS WEST SIDE WHICH WILL RUN OVER THE LOCAL AREA THIS WEEKEND DROPPING TEMPERATURES SIGNIFICANTLY BELOW AVERAGE ONCE AGAIN AND CREATING CONDITIONS FOR ACCUMULATING SNOW. BASED ON QPF IN THE 12Z MODELS INCREASED CHANCE POPS FOR SATURDAY NIGHT. SUNDAY NIGHT THE WAVE MOVES TO OUR SOUTH WILL BE REPLACED BY AN ARCTIC SURFACE HIGH...ENDING ANY SNOW THREAT. THE ARCTIC AIR QUICKLY MOVES ON BY TUESDAY AS WARMER AIR PUSHES IN FROM THE WEST. ADJUSTED SUNDAY/SUNDAY NIGHT TEMPS DOWN IN COORDINATION WITH SURROUNDING OFFICES. FEW OTHER CHANGES WERE NECESSARY TO THE EXTENDED FORECAST..OTHER THAN FOR BORDER COORDINATION. SCT PREVIOUS DISCUSSION... THURSDAY NIGHT THROUGH FRIDAY...AN UPPER LEVEL SHORTWAVE SLIDES DOWN THE EASTERN SIDE OF LARGE UPPER LEVEL RIDGE OVER THE WEST COAST. THIS WILL PUSH A WEAK BACK DOOR COLD FRONT INTO EASTERN MONTANA. MODELS ARE HINTING AT SOME LIGHT QPF FOR THE EASTERN ZONES BUT THE MAJORITY OF THE QPF REMAINS IN NORTH DAKOTA. THERE IS A SMALL AMOUNT OF QPF THAT MAKES IT INTO THE NORTHEASTERN ZONES BUT THE MODELS VERY ON THE DEGREE OF MOISTURE DECIDE TO CONTINUE WITH DRY CONDITIONS THAT WERE ALREADY IN THE ZONES. THE ONE THING THIS SHORTWAVE WILL DO ON FRIDAY IS SINK DOWN TOWARD THE OHIO VALLEY AND OPEN UP A LARGE UPPER TROUGH OVER THE SOUTHERN PLAINS. THIS WILL FORCE THE UPPER RIDGE BACK OVER THE PACIFIC WHICH WILL OPEN UP THE GULF OF ALASKA UP TO TRANSPORT MOISTURE INTO THE NORTHERN PLAINS FRIDAY NIGHT THROUGH SUNDAY NIGHT. FRIDAY NIGHT THROUGH SATURDAY NIGHT IS A LITTLE IFFY AT THIS POINT WITH THE WEAK COLD FRONT ACROSS THE REGION. 850 BM TEMPERATURES WARM UP ABOVE FREEZING OVER THE WESTERN ZONES AND THE GFS BUFR SOUNDINGS ARE SHOWING FREEZING DRIZZLE OR A WINTRY MIX. THE HUDSON BAY LOW WILL SEND ANOTHER SHOT OF ARCTIC AIR TOWARDS NEMONT. THE STRONG ARCTIC FRONT WILL ARRIVE SATURDAY NIGHT AND ALL PRECIPITATION SHOULD CHANGE OVER TO SNOW AT THAT POINT. IT LOOKS LIKE THE PRECIP WILL LAST UNTIL MONDAY MORNING BEFORE THE FRONT TAKE THE BULK OF THE PRECIPITATION SOUTH OF THE REGION. MONDAY THROUGH TUESDAY MORNING WILL BE ANOTHER EXTREMELY COLD PERIOD ACROSS THE REGION. SLIGHT WARMING ON TUESDAY THROUGH WEDNESDAY WITH DRY CONDITIONS. RSMITH && .AVIATION... AN UPPER LEVEL RIDGE PARKED ALONG THE WEST COAST WILL MAINTAIN NORTHERLY FLOW ALOFT OVER EASTERN MONTANA TONIGHT AND WEDNESDAY. SATELLITE IMAGERY REVEALS FEW...IF ANY...CLOUDS UP-STREAM IN THE UPPER FLOW. THE ARRIVAL OF A WARM FRONT WEDNESDAY WILL BRING IN SOME MID-LEVEL CLOUDS BY AFTERNOON. WITH SURFACE HIGH PRESSURE IN PLACE TONIGHT OVER THE REGION...CONDITIONS WILL REMAIN VFR AT ALL TERMINALS...EXCEPT FOR PATCHY FREEZING FOG THAT MIGHT DEVELOP LATER TONIGHT AND WEDNESDAY MORNING. GENERALLY SOUTHWESTERLY WINDS WILL RANGE AROUND 5 TO 10 KTS. SCT && .GLASGOW WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL 11 AM MST WEDNESDAY FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...DANIELS... SHERIDAN...WESTERN ROOSEVELT...GARFIELD...MCCONE...RICHLAND... DAWSON...PRAIRIE...WIBAUX...NORTHERN PHILLIPS...NORTHERN VALLEY...EASTERN ROOSEVELT. && WEATHER.GOV/GLASGOW
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GLASGOW MT 241 PM MST TUE FEB 1 2011 MTZ016>020-022>027-059-061-062-021300- CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY- DANIELS-SHERIDAN-WESTERN ROOSEVELT-GARFIELD-MCCONE-RICHLAND- DAWSON-PRAIRIE-WIBAUX-NORTHERN PHILLIPS-NORTHERN VALLEY- EASTERN ROOSEVELT- 241 PM MST TUE FEB 1 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT COLD TEMPERATURES AND WIND CHILLS ARE EXPECTED TO CONTINUE THROUGH THE LATE MORNING HOURS ON WEDNESDAY AND A WIND CHILL ADVISORY IS IN EFFECT FOR MOST OF NORTHEAST MONTANA. TEMPERATURE READINGS OF 15 TO 30 BELOW ZERO ARE POSSIBLE...AND WILL COMBINE WITH A SOUTHEAST WIND AROUND 5 MPH TO PRODUCE WIND CHILLS OF 20 TO 40 BELOW ZERO. THESE WIND CHILL CONDITIONS CAN CAUSE FROSTBITE ON EXPOSED SKIN WITHIN 30 MINUTES. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .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.
10 extreme cold/wind chill. Local standard time, as filed.
Beginning at 1800 MST, the Hillside DOT sensor had -40F wind chills.
At 1900 MST, the Glasgow ASOS had more than 2 hours of -40F wind chills.
At 1900 MST, the Beaver Hill DOT sensor had more than 2 hours of -40F wind chills.
At 2000 MST, McDonalds DOT sensor had more than 2 hours of -40F or colder wind chills.
At 2000 MST, the Sidney AWOS had more than 2 hours of -40F wind chills.
At 2300 MST, Bluff Creek RAWS had more than 2 hours of -40F wind chills.
At 2200 MST, the Cow Creek DOT sensor had more than 2 hours of -40F wind chills.
At 1800 MST, the Comertown DOT sensor and Medicine Lake RAWS observed more than 2 hours of -40F or below.
At 2300 MST, the Malta Handar had wind chills of -40F for over 2 hours.
At midnight MST, the Poplar RAWS and Stateline DOT sensors had -40F wind chills for more than 2 hours.
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 2026-10-01. Each event’s entry at NCEI: 273838, 273835, 273841, 273836, 273840, 273830, 273839, 273832, 273833, 273837.