Ice jamming of portions of the Missouri River caused minor flooding within the City of Great Falls. A segment of Lower River Drive in Great Falls was closed.
Every event with a place to put it. 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 TFX wrote it up.
Ice jamming of portions of the Missouri River caused minor flooding within the City of Great Falls. A segment of Lower River Drive in Great Falls was closed.
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 Great Falls, MT wrote its last area forecast discussion before the first event at Dec 20, 10:45 AM MST, 3 hours 13 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 1045 AM MST MON DEC 20 2010 .UPDATE... SNOW CONTINUES TO DISSIPATE ACROSS EASTERN PORTIONS OF THE FORECAST AREA SO HAVE CANCELLED ALL REMAINING WARNINGS AND ADVISORIES. LIGHT SNOW WILL CONTINUE AROUND THE LITTLE BELT MTNS INTO JUDITH BASIN COUNTY AND PARTS OF FERGUS AND BLAINE COUNTIES THRU THIS MORNING...BUT MOST LOCATIONS WILL ONLY SEE AN ADDITIONAL INCH OF SNOW OR LESS. WARANAUSKAS && .AVIATION... UPDATED 1750Z. LIGHT SNOW IS BEGINNING TO COME TO AN END OVER MUCH OF THE REGION...WITH A FEW LIGHT SNOW SHOWERS CONTINUING MAINLY IN THE HAVRE AND LEWISTOWN AREAS. THE SNOW SHOULD END IN THESE REGIONS BY MID AFTERNOON. MOUNTAIN TOPS EAST OF GREAT FALLS WILL BE OBSCURED THROUGH LATE AFTERNOON. EXPECT CLEARING THIS EVENING...WITH AREAS OF FOG DEVELOPING OVER THE REGION AFTER 06Z TUE. THE FOG COULD BE DENSE IN A FEW LOCATIONS BY 12Z TUE. FOR NOW...I WILL HOLD OFF IN PUTTING IN DENSE FOG IN THE TAFS...BUT THE POTENTIAL IS THERE AND WE WILL CONTINUE TO MONITOR IT CLOSELY. BRUSDA && .PREV DISCUSSION... /ISSUED 542 AM MST MON DEC 20 2010/ TODAY THROUGH WEDNESDAY...SHORT WAVE ENERGY CONTINUES TO BE EJECTED FROM THE UPPER TROF ALONG THE WEST COAST AND RIDE THE SOUTHWEST FLOW ALOFT OVER THE AREA. WITH JET DYNAMICS...STEEP LAPSE RATES AND PLENTY OF MOISTURE...CONDITIONS CONTINUE RIPE FOR A WIDESPREAD SNOW EVENT. RADAR RETURNS CONTINUE TO SHOW THE MAIN BAND OF SNOW EXTENDING ACROSS CENTRAL MONTANA AND SATELLITE IMAGERY SHOWS THE VORT CENTER OVER SOUTHWEST MONTANA. SNOW IS WINDING DOWN OVER BEAVERHEAD COUNTY AND WILL LIKELY END THE WINTER STORM WARNING AT 5 AM. THE REMAINDER OF THE HIGHLIGHTS WILL CONTINUE. MODELS CONTINUE TO INDICATE A GRADUALLY CESSATION OF PRECIPITATION BY EARLY AFTERNOON WITH RAPID IMPROVEMENT OF CONDITIONS BEGINNING IN THE WEST AND WORKING EAST. UPPER RIDGING BEGINS TO DEVELOP TONIGHT AND CONTINUES INTO WEDNESDAY FOR DRYING AND MODERATING CONDITIONS. BY WEDNESDAY...THE WEST COAST UPPER TROF MOVES INLAND AND OVER THE PACIFIC NORTHWEST. INCREASING SOUTHWEST FLOW ALOFT WILL BRING ANOTHER ROUND OF MOISTURE TO SOUTHWEST MONTANA AND SCATTERED SNOW TO THE MOUNTAINS. TEMPERATURES WILL BEGIN A SLOW WARMING TREND TODAY BUT READINGS WILL REMAIN BELOW SEASONAL AVERAGES THROUGH MIDWEEK. EMANUEL WEDNESDAY NIGHT THROUGH MONDAY...MEDIUM RANGE MODELS REMAIN IN FAIR AGREEMENT ON THE OVERALL PATTERN THROUGH EARLY THIS WEEKEND BEFORE DIVERGING SOME TOWARDS EARLY NEXT WEEK. PERIOD BEGINS WITH A SPLIT FLOW ALOFT OVER THE WESTERN U.S. WITH SOME WEAK ENERGY LIFTING NE THROUGH THE REGION WED NIGHT AND THURS. MODELS SHOW SOME DIFFERENCES WITH HOW MUCH MOISTURE WILL BE PRESENT AS THE ENERGY MOVES ACROSS...LEADING TO SOMEWHAT HIGHER UNCERTAINTY DURING THIS PERIOD...HOWEVER EXPECT ANY PRECIP AMOUNTS TO BE LIGHT WITH A LACK OF STRONG FORCING. SURFACE HIGH PRESSURE REMAINS TO THE NE WITH EAST TO SE WINDS LIKELY KEEPING THE COOLER AIRMASS IN PLACE OVER THE PLAINS THROUGH FRIDAY WITH WARMING ARRIVING FIRST AT HIGHER ELEVATIONS AND OVER SW MT. UPPER LEVEL RIDGING AMPLIFIES OVER THE REGION FRIDAY AND SATURDAY DOWNSTREAM OF A DEEPENING TROUGH OFF THE WEST COAST. THIS WILL PROVIDE DRY AND MILD CONDITIONS CHRISTMAS EVE AND CHRISTMAS DAY AS SOUTHERLY FLOW AT ALL LEVELS AND STRONGER WARMING ALOFT PUSHES TEMPS TO SLIGHTLY ABOVE SEASONAL AVERAGES BY CHRISTMAS DAY. MODELS AGREE TO BREAK DOWN THIS RIDGE DURING THE SATURDAY NIGHT THROUGH MONDAY PERIOD BUT DIFFER IN HOW THEY ACCOMPLISH THIS. IN ANY CASE...PRECIPITATION CHANCES WILL INCREASE LATE THIS WEEKEND INTO EARLY NEXT WEEK WITH TEMPERATURES NEAR SEASONAL AVERAGES. HOENISCH && .PRELIMINARY POINT TEMPS/POPS... GTF 14 10 28 13 / 80 10 10 0 CTB 10 4 22 8 / 60 10 10 0 HLN 20 7 20 8 / 50 20 10 10 BZN 21 2 22 3 / 20 10 10 10 WEY 22 6 23 7 / 70 40 20 40 DLN 24 7 23 7 / 20 20 10 10 HVR 8 -3 11 -1 / 90 20 10 0 LWT 12 6 29 10 / 100 10 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...WARANAUSKAS LONG TERM...HOENISCH AVIATION...BRUSDA WEATHER.GOV/GREATFALLS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 1016 AM MST MON DEC 20 2010 MTZ008>015-044>055-211200- BEAVERHEAD-NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER-HILL- CASCADE-CHOUTEAU-CENTRAL AND SOUTHERN LEWIS AND CLARK-MADISON- TOOLE-LIBERTY-EASTERN PONDERA-BLAINE- SOUTHERN ROCKY MOUNTAIN FRONT-EASTERN TETON-JUDITH BASIN-FERGUS- JEFFERSON-BROADWATER-MEAGHER-GALLATIN- 1016 AM MST MON DEC 20 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1150 AM MST MON DEC 20 2010
..TIME.. ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE.. ....MAG.... ..COUNTY LOCATION.. ST.. ...SOURCE....
..REMARKS..
1000 AM SNOW 14 SW STOCKETT 47.22N 111.39W
12/20/2010 M5.0 INCH CASCADE MT TRAINED SPOTTER
5 INCHES OF NEW SNOW SINCE LAST NIGHT.
&&
JOHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1153 AM MST MON DEC 20 2010
..TIME.. ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE.. ....MAG.... ..COUNTY LOCATION.. ST.. ...SOURCE....
..REMARKS..
1000 AM SNOW DILLON 45.22N 112.63W
12/20/2010 E2.0 INCH BEAVERHEAD MT LAW ENFORCEMENT
2 INCHES OF NEW SNOW IN THE DILLON AREA OVERNIGHT.
&&
BRUSDAPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1203 PM MST MON DEC 20 2010
..TIME.. ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE.. ....MAG.... ..COUNTY LOCATION.. ST.. ...SOURCE....
..REMARKS..
1200 PM SNOW 3 N WOLF CREEK 47.05N 112.07W
12/20/2010 E5.0 INCH LEWIS AND CLARK MT TRAINED SPOTTER
5 INCHES OF NEW SNOW IN THE PAST 24 HOURS JUST NORTH OF
WOLF CREEK.
&&
BRUSDAPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1218 PM MST MON DEC 20 2010
..TIME.. ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE.. ....MAG.... ..COUNTY LOCATION.. ST.. ...SOURCE....
..REMARKS..
0800 AM SNOW 1 W MOCCASIN 47.05N 109.93W
12/20/2010 M6.0 INCH JUDITH BASIN MT PUBLIC
6 INCHES OF NEW SNOW IN THE PAST 24 HOURS AT THE MSU
CENTRAL AG RESEARCH CENTER.
&&
BRUSDAPRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE GREAT FALLS MT
1239 PM MST MON DEC 20 2010
..TIME.. ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE.. ....MAG.... ..COUNTY LOCATION.. ST.. ...SOURCE....
..REMARKS..
0642 PM SNOW 1 SE WEST YELLOWSTONE 44.66N 111.10W
12/19/2010 E2.0 INCH GALLATIN MT LAW ENFORCEMENT
0400 AM SNOW 1 SW LAKEVIEW 44.59N 111.82W
12/20/2010 M4.0 INCH BEAVERHEAD MT MESONET
4 INCHES OF NEW SNOW IN THE PAST 24 HOURS ENDING AT 4
AM MONDAY.
0500 AM SNOW 3 ENE HELENA 46.61N 111.96W
12/20/2010 M2.5 INCH LEWIS AND CLARK MT OFFICIAL NWS OBS
2.5 INCHES OF NEW SNOW SINCE 5 PM SUNDAY EVENING AT THE
HELENA REGIONAL AIRPORT.
0700 AM SNOW HOBSON 47.00N 109.87W
12/20/2010 M5.5 INCH JUDITH BASIN MT TRAINED SPOTTER
5.5 INCHES OF NEW SNOW FELL IN THE HOBSON AREA
OVERNIGHT.
0700 AM SNOW 7 S NEIHART 46.84N 110.72W
12/20/2010 E4.0 INCH MEAGHER MT PUBLIC
4 INCHES OF NEW SNOW OVERNIGHT.
0730 AM SNOW 5 SW GREAT FALLS 47.46N 111.38W
12/20/2010 M4.5 INCH CASCADE MT OFFICIAL NWS OBS
4.5 INCHES OF NEW SNOW SINCE 5 PM SUNDAY EVENING AT
GREAT FALLS WEATHER OFFICE.
0800 AM SNOW 4 W HAVRE 48.54N 109.77W
12/20/2010 M2.5 INCH HILL MT OFFICIAL NWS OBS
2.5 INCHES OF NEW SNOW SINCE 10 PM SUNDAY EVENING.
CURRENT SNOW DEPTH IS 7 INCHES.
0800 AM SNOW 1 SSW FORT BELKNAP 48.47N 108.77W
12/20/2010 M3.0 INCH BLAINE MT TRAINED SPOTTER
3 INCHES OF NEW SNOW SINCE MIDNIGHT.
0800 AM SNOW 5 NE DILLON 45.27N 112.56W
12/20/2010 E4.0 INCH BEAVERHEAD MT OFFICIAL NWS OBS
4 INCHES OF NEW SNOW AT THE DILLON AIRPORT OVER THIS
PAST WEEKEND.
0800 AM SNOW 2 SW LEWISTOWN 47.04N 109.46W
12/20/2010 E4.0 INCH FERGUS MT OFFICIAL NWS OBS
4 INCHES OF NEW SNOW OVER THIS PAST WEEKEND AT THE
LEWISTOWN AIRPORT.
0800 AM SNOW HIGHWOOD 47.58N 110.79W
12/20/2010 M4.1 INCH CHOUTEAU MT PUBLIC
REPORT VIA COCORAHS...4.1 INCHES OF NEW SNOW IN
HIGHWOOD.
0800 AM SNOW 18 SSW FORESTGROVE 46.77N 109.28W
12/20/2010 M2.0 INCH FERGUS MT PUBLIC
2 INCHES OF NEW SNOW IN THE PAST 24 HOURS IN THE HALF
MOON PASS AREA.
0800 AM SNOW 1 W MOCCASIN 47.05N 109.93W
12/20/2010 M6.0 INCH JUDITH BASIN MT PUBLIC
6 INCHES OF NEW SNOW IN THE PAST 24 HOURS AT THE MSU
CENTRAL AG RESEARCH CENTER.
0807 AM SNOW 1 N HELENA 46.60N 112.02W
12/20/2010 M3.8 INCH LEWIS AND CLARK MT PUBLIC
3.8 INCHES OF NEW SNOW SINCE LAST NIGHT.
0900 AM SNOW 3 SW CUT BANK 48.61N 112.38W
12/20/2010 E2.0 INCH GLACIER MT OFFICIAL NWS OBS
2 INCHES OF NEW SNOW OVER THIS PAST WEEKEND AT THE CUT
BANK AIRPORT.
0900 AM SNOW FORT BENTON 47.83N 110.66W
12/20/2010 M3.5 INCH CHOUTEAU MT CO-OP OBSERVER
3.5 INCHES OF NEW SNOW IN THE PAST 24 HOURS IN FORT
BENTON.
0900 AM SNOW 1 SSE WEST YELLOWSTONE 44.65N 111.10W
12/20/2010 M5.5 INCH GALLATIN MT CO-OP OBSERVER
5.5 INCHES OF NEW SNOW IN THE WEST YELLOWSTONE AREA IN
THE PAST 24 HOURS.
1000 AM SNOW 14 SW STOCKETT 47.22N 111.39W
12/20/2010 M5.0 INCH CASCADE MT TRAINED SPOTTER
5 INCHES OF NEW SNOW SINCE LAST NIGHT.
1000 AM SNOW DILLON 45.22N 112.63W
12/20/2010 E2.0 INCH BEAVERHEAD MT LAW ENFORCEMENT
2 INCHES OF NEW SNOW IN THE DILLON AREA OVERNIGHT.
1200 PM SNOW 3 N WOLF CREEK 47.05N 112.07W
12/20/2010 E5.0 INCH LEWIS AND CLARK MT TRAINED SPOTTER
5 INCHES OF NEW SNOW IN THE PAST 24 HOURS JUST NORTH OF
WOLF CREEK.
&&
BRUSDAPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1251 PM MST MON DEC 20 2010
..TIME.. ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE.. ....MAG.... ..COUNTY LOCATION.. ST.. ...SOURCE....
..REMARKS..
1200 PM SNOW 7 SE ROCKY BOY 48.18N 109.69W
12/20/2010 E3.5 INCH HILL MT TRAINED SPOTTER
3.5 INCHES OF NEW SNOW IN THE PAST 24 HOURS.
&&
BRUSDAThe national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
Ice jamming on the Missouri River in Great Falls caused minor flooding of Lower River Road. A portion of the road was closed for several days.
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: 273593.