A strong, moist subtropical jet stream overran an arctic front to bring a west to east strip of heavy snow across northeast Montana. Amounts close to a foot were common from Glasgow east to Richland county.
Every event with a place to put it; 12 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.
A strong, moist subtropical jet stream overran an arctic front to bring a west to east strip of heavy snow across northeast Montana. Amounts close to a foot were common from Glasgow east to Richland county.
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 Dec 19, 9:29 PM MST, 2 hours 31 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GLASGOW MT 929 PM MST SUN DEC 19 2010 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH TUESDAY... STORM SYSTEM COMING INTO THE REGION LOOKS TO BE ON TRACK WITH NEWER 18 AND 00Z NAM SHOWING A FAIRLY STABLE PATTERN IN QPF AND SURFACE FEATURES FROM RUN TO RUN. IT LOOKS AT THIS TIME LIKE THE BULK FO THE SNOWFALL WILL OCCUR IN A NARROW BAND JUST NORTH OF THE FRONT AND THEREFORE WILL BE AT ITS STRONGEST ACROSS A LINE FROM SYDNEY... TO WOLF POINT... TO GLASGOW... AND FINALLY MALTA. THEREFORE HAVE DECIDED TO BUMP THE WATCH ACROSS THESE REGIONS TO A FULL FLEDGED WARNING. TEMPERATURES TONIGHT WERE ALSO ADJUSTED FOR INCOMING CLOUD COVER FROM THE SOUTH AND MILK AND MISSOURI VALLEY DRAINAGE WINDS ACROSS THE NORTH. GAH PREVIOUS SHORT TERM DISCUSSION... THE PACIFIC STORM SYSTEM OFF THE PACNW COAST WILL SEND A STRONG WAVE AND ABUNDANT MOISTURE INTO MONTANA TONIGHT AND MONDAY. MODELS DO DIFFER IN TIMING AND LOCATION. THE ECMWF IS THE MOST WIDESPREAD MODEL FOR QPF AND THE MET SEEMS TO BE THE MODEL OF CHOICE DUE TO CONSISTENCY. THE GFS HAS WANDERED ABOUT AND IS NOT CONSISTENT. THEREFORE WILL BE LEANING ON THE NAM THE MOST. THE GOES IR IMAGERY SHOWS THE MID TO HIGH CLOUDS MOVING INTO SOUTHWESTERN MONTANA THIS MORNING...WHICH SHOULD BEGIN TO SPREAD OVER OUR SOUTHWEST THIS EVENING. A BROAD CLOSED 700MB LOW AND CLOSED SURFACE LOW WITH WIDESPREAD OMEGA LIFT WILL RUN OVER THE ARCTIC BOUNDARY TO OUR SOUTH AND RUN INTO THE ARCTIC AIR OF THE CWA. WITH FOCUSED LIFT THIS SNOW EVENT COULD PRODUCE A SNOW BAND OF ENHANCED OR HEAVY SNOWFALL. THE WAVE WILL ENTER THE CWA IN THE SOUTHWEST ZONES AFTER MIDNIGHT AND DUMP SNOW MOSTLY SOUTH OF THE MISSOURI RIVER. THEN THE SNOW SPREADS NORTH OF THE RIVER BEFORE NOON MONDAY. THE HEAVY SNOW CONTINUES NORTH AND EAST IN THE AFTERNOON AND EVENING WITH WESTERN AREAS TAPERING OFF. EXCEPT FOR A BAND OF LIGHT SNOW ACROSS THE NORTHEASTERN ZONES THE STORM WILL BE OUT OF THE AREA BY AROUND MIDNIGHT. WITH QPF OF AROUND 0.15 TO 0.35 INCH AND A SNOW RATIO OF AROUND 20:1 SNOW AMOUNTS OF 6 TO 11 INCHES IN THE WINTER STORM WATCH STILL LOOK REASONABLE. WITH THE 850MB AND 700MB PRESSURE GRADIENT TIGHTENING UP AS THE LOW MOVES NORTH INTO THE AREA...NORTHERLY WINDS OF AROUND 15 TO 25 KTS ARE POSSIBLE WHICH COULD GENERATE BLOWING AND DRIFTING SNOW. THE WINDS WILL SHIFT AROUND TO THE NORTHWEST AS THE LOW MOVES EAST. IN AREAS OF HEAVY SNOW...VISIBILITIES COULD DROP TO LESS THAN A HALF OR QUARTER MILE AT TIMES. WILL ISSUE WINTER STORM WARNING FOR SNOW AND BLSN IN ZONES SOUTH OF THE MISSOURI RIVER BEGINNING 6Z AND LEAVE THE REST OF THE AREA UNDER A WINTER STORM WATCH BEGINNING 12Z TO LET THE NIGHT SHIFT HAVE A FINAL LOOK AT THE LATEST MODELS. ALSO WILL ISSUE A WIND CHILL ADVISORY FOR THE NORTHERN COUNTIES LATE TONIGHT BASED ON WIND STRENGTH AND LOW TEMPERATURES. TUESDAY...A WEAK UPPER SHORT WAVE WILL MOVE OVER THE AREA ALONG WITH A SURFACE RIDGE. THIS COULD SET UP A MOSTLY QUIET PERIOD WITH SCATTERED TO BROKEN LOW STRATUS WITH MORE FLURRIES POSSIBLE. WINDS WILL STAY BELOW 10KTS. SCT .LONG TERM...TUESDAY NIGHT THROUGH SUNDAY... NO SIGNIFICANT CHANGES MADE TO THE EXTENDED FORECAST. STILL MUCH UNCERTAINTY WITH THE EVENTUAL OUTCOME WED NIGHT INTO THURSDAY. IT APPEARS THE MAJORITY OF UPPER LEVEL ENERGY WILL MOVE ACROSS THE CENTRAL ROCKIES...BUT THERE IS A WEAKER WAVE THAT MOVES ACROSS MONTANA DURING THE SAME TIME. ASSOCIATED MOISTURE WOULD RISE OVER THE QUASI-STATIONARY ARCTIC BOUNDARY IN OUR VICINITY AND LIKELY RESULT IN SOME LIGHT SNOW. WILL LEAVE POPS IN THE 20 TO 30 PERCENT RANGE FOR NOW. THE ONLY MINOR CHANGES MADE WERE TO COOL TEMPS A BIT OVER THE PREVIOUS FORECAST. ARCTIC HIGH PRESSURE REMAINS ANCHORED OVER MANITOBA THROUGH THE END OF THE WEEK AND WILL LIKELY KEEP TEMPS BELOW NORMAL FOR MUCH OF THE AREA SAVE THE HIGHER AREAS ACROSS SOUTHWEST PORTIONS. SOME MODERATION POSSIBLE BY THE CHRISTMAS WEEKEND AS MODELS ARE IN DECENT AGREEMENT AMPLIFYING A LONGWAVE UPPER LEVEL RIDGE OVER THE REGION. BMOYER PREVIOUS DISCUSSION... THE MODELS DEPICT THAT THE WESTERN STATES WILL BE INFLUENCED BY A RIDGE FOR MOST OF THE EXTENDED FORECAST. THE RIDGE WILL STRENGTHEN AND EXTEND INTO CENTRAL CANADA AS A LONGWAVE TROUGH OFF THE WEST COAST DEEPENS AND PUSHES ONSHORE. AS THE TROUGH MOVES INLAND...A STORM SYSTEM WILL DEVELOP AND MOVE THROUGH THE CENTRAL ROCKIES BY THURSDAY. THE MOISTURE PUMPED IN ALOFT WILL SLIDE NORTHEAST AS FAR AS THE DAKOTAS. WRAP AROUND FLOW WITH THIS SYSTEM COULD BRING SNOW TO PORTIONS OF EASTERN MONTANA THROUGH THURSDAY NIGHT. AFTER THE STORM SYSTEM PASSES THROUGH THE NORTHERN PLAINS THE RIDGE WILL BEGIN TO REBOUND FRIDAY. SLIGHTLY WARMER TEMPERATURES WILL MOVE INTO NORTHEAST MONTANA THROUGH THE END OF THE FORECAST AS THE RIDGE STRENGTHENS. THE MODELS BEGIN SLIPPING OUT OF AGREEMENT SUNDAY NIGHT...BUT THEY HINT AT THE RIDGE BREAKING DOWN BY ANOTHER SYSTEM PLOWS THROUGH THE ROCKIES. CHANCES FOR PRECIPITATION WERE NOT MENTIONED DUE TO UNCERTAINTY OF THE STORM TRACK. AES && .AVIATION... CLOUDS WILL INCREASE AND CEILINGS WILL LOWER OVER THE TAF SITES OVERNIGHT. THE MAIN IMPACT IN THE NEXT 24 HOURS WILL BE THE ONSET AND INTENSITY OF SNOWFALL EXPECTED TO MOVE INTO TAF SITES BETWEEN 08Z AND 12Z. AT THIS RANGE...HAVE INTRODUCED MVFR CONDITIONS WITH -SN BEGINNING 08Z TO 12Z...WITH A REDUCTION TO IFR CONDITIONS AND GUSTY WINDS BY MID MORNING MONDAY. VLIFR CONDITIONS MAY OCCUR AT TIMES ON MONDAY DEPENDING ON EXACTLY WHERE THE EXPECTED HEAVIER SNOW BANDS SET UP. SNOW WILL MOVE TO THE EAST MONDAY EVENING IMPROVING VISIBILITY BACK UP TO 7 MILES OR MORE. HOWEVER...LOOK FOR MVFR CEILINGS TO LINGER MONDAY NIGHT. && .GLASGOW WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING FROM 6 AM MONDAY TO MIDNIGHT MST MONDAY NIGHT FOR CENTRAL AND SOUTHERN VALLEY...DANIELS...SHERIDAN... WESTERN ROOSEVELT...RICHLAND...NORTHERN PHILLIPS...NORTHERN VALLEY...EASTERN ROOSEVELT. WIND CHILL ADVISORY UNTIL 6 AM MST MONDAY FOR CENTRAL AND SOUTHERN VALLEY...DANIELS...SHERIDAN...WESTERN ROOSEVELT... NORTHERN PHILLIPS...NORTHERN VALLEY...EASTERN ROOSEVELT. WINTER STORM WARNING UNTIL 9 PM MST MONDAY FOR CENTRAL AND SOUTHEAST PHILLIPS...PETROLEUM...GARFIELD...MCCONE...DAWSON... PRAIRIE...WIBAUX...SOUTHWEST PHILLIPS. && WEATHER.GOV/GLASGOW
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GLASGOW MT 917 PM MST SUN DEC 19 2010 MTZ017>020-059-061-062-201300- CENTRAL AND SOUTHERN VALLEY-DANIELS-SHERIDAN-WESTERN ROOSEVELT- NORTHERN PHILLIPS-NORTHERN VALLEY-EASTERN ROOSEVELT- 917 PM MST SUN DEC 19 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...TONIGHT A WIND CHILL ADVISORY IS IN EFFECT FOR WIND CHILLS OF 20 TO 35 BELOW ZERO FOR MOST OF THE AREA NORTH OF MISSOURI RIVER TONIGHT. EXPECT OVERNIGHT LOW TEMPERATURES OF ZERO TO 10 DEGREES BELOW ZERO WITH STRONG NORTHEAST WINDS OF 15 TO 25 MPH. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY A WINTER STORM WARNING IS IN EFFECT FROM 6 AM MONDAY MORNING TO MIDNIGHT MONDAY NIGHT FOR HEAVY SNOW OF 6 TO 11 INCHES TOTAL. IN ADDITION... STRONG NORTH TO NORTHEAST WINDS OF AROUND 15 TO 25 MPH WILL CAUSE BLOWING AND DRIFTING SNOW REDUCING VISIBILITIES TO AROUND ONE HALF MILE AT TIMES AND CAUSE HAZARDOUS TRAVEL CONDITIONS. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. MTZ016-021>027-060-201300- CENTRAL AND SOUTHEAST PHILLIPS-PETROLEUM-GARFIELD-MCCONE-RICHLAND- DAWSON-PRAIRIE-WIBAUX-SOUTHWEST PHILLIPS- 917 PM MST SUN DEC 19 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...TONIGHT A WINTER STORM WARNING IS IN EFFECT FROM MIDNIGHT TONIGHT TO 9 PM MONDAY EVENING FOR HEAVY SNOW OF 6 TO 10 INCHES TOTAL. IN ADDITION... STRONG NORTH TO NORTHEAST WINDS OF AROUND 15 TO 25 MPH WILL CAUSE BLOWING AND DRIFTING SNOW REDUCING VISIBILITIES TO AROUND ONE HALF MILE AT TIMES AND CAUSE HAZARDOUS TRAVEL CONDITIONS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY HEAVY SNOW WILL CONTINUE DURING THE DAY MONDAY AND DIMINISH MONDAY EVENING. .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.
12 winter storm. Local standard time, as filed.
Snowfall ranged from 6.1 inches at the NWS Glasgow office to 12 inches at Park Grove. Most areas reported about 10 to 11 inches as the lower amounts were likely wind blown.
Coop observer in Malta observed 6 inches of new snow.
At least 6 inches of snow fell across the area with greatest amounts likely to have occurred in the central and eastern portions of the zone.
Snow amounts of up to 9 inches were reported across the area.
Two miles south of Whitewater, the spotter estimated 6 inches of snowfall.
Observer 12 miles south-southeast of Opheim reported 6.5 inches of snowfall.
Spotter observed 6.5 inches of snow in Navajo.
Observer 7 miles east-northeast of Medicine Lake observed 7 inches of snow, with snow falling between 0700 and 1600 MST. County official estimated 8 inches of new snowfall.
Department of Highways measured 11 inches, while a trained observer reported 9 inches.
Trained observer 2 miles north-northeast of Froid reported 9 inches of new snow. Culbertson Coop reported 8 inches of new snowfall.
Spotters reported 6 to 8 inches of snow across the area.
Five to eight inches of snowfall were common across the area.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2010Every state in 2010This day in weather historyWarnings in Montana, 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: 267211, 267212, 276297, 276303, 267032, 267033, 267213, 267214, 267215, 267216, 276306, 276309.