Low pressure moving across southern Canada contributed to a tight surface gradient and the development of strong winds along the Rocky Mountain Front and adjacent plains. Wind gusts in excess of 60 mph were reported.
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.
Low pressure moving across southern Canada contributed to a tight surface gradient and the development of strong winds along the Rocky Mountain Front and adjacent plains. Wind gusts in excess of 60 mph were reported.
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 Nov 12, 4:35 PM MST, 3 hours 40 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 435 PM MST SAT NOV 12 2011 .DISCUSSION... THIS EVENING THROUGH MONDAY EVENING...UPPER LEVEL TROF THAT MOVED ACROSS THE FORECAST AREA EARLIER TODAY IS NOW IN SOUTH CENTRAL AND ERN MT. OTHER THAN A FEW SCATTERED SNOW SHOWERS OVER THE SOUTHWEST MTNS AND THE ROCKY MTN FRONT...SNOW HAS PRETTY MUCH ENDED ACROSS THE REGION SO HAVE CANCELED ALL WINTER WEATHER ADVISORIES. HOWEVER OUR BREAK FROM THE ACTIVE WEATHER WILL BE SHORT-LIVED AS THE NEXT SYSTEM IS ALREADY INTO CENTRAL WASHINGTON WITH THE LEADING EDGE OF ITS MOISTURE PUSHING STEADILY INTO WESTERN MT. PERSISTENT NORTHWEST FLOW ALOFT WILL BRING THE SYSTEM EAST OF THE CONTINENTAL DIVIDE TOMORROW MORNING WITH ANOTHER ROUND OF SNOWSHOWERS PRIMARILY OVER CENTRAL AND SOUTHWEST COUNTIES. THE GRADIENT BETWEEN THE UPPER TROF AND THE LARGE HIGH PRESSURE RIDGE OFF THE PACIFIC COAST WILL ALSO BRING HIGH WINDS TO THE ROCKY MTN FRONT AND ADJACENT PLAINS SO HAVE ISSUED A HIGH WIND WARNING FOR THAT LOCATION BEGINNING AT 11 PM AND LASTING THRU THE DAYTIME HOURS ON SUNDAY. THE PARADE OF WINTER TYPE SYSTEMS CONTINUES ON MONDAY AS ANOTHER SHORTWAVE TROF DROPS IN QUICKLY FROM BRITISH COLUMBIA. FORECAST MODELS ARE INDICATING THIS ONE MAY A BIT MORE ASSOCIATED MOISTURE AND A COOLER AIRMASS...PROVIDING A BETTER CHANCE FOR SNOW OVER MUCH OF THE REGION. RIGHT NOW ACCUMULATIONS STILL LOOK ON THE LIGHT SIDE...1-3 INCHES IN THE VALLEYS/3-6 INCHES IN THE MTNS. TEMPERATURES TOMORROW WILL BE SIMILAR TO TODAY...MID 30S TO LOW 40S BUT COOL BY ABOUT 5-8 DEGREES ON MONDAY. WARANAUSKAS MONDAY NIGHT THROUGH SATURDAY...UNSETTLED WEATHER WILL CONTINUE THROUGH THE MEDIUM RANGE PERIOD. SCATTERED SNOW SHOWERS ON TUESDAY WILL DECREASE IN AREAL COVERAGE ON WEDNESDAY. BOTH THE GFS AND EUROPEAN MODELS DEVELOP AN UPPER RIDGE OVER THE AREA WEDNESDAY AFTERNOON BUT THE GFS HAS LESS AMPLITUDE OF THE RIDGE THAN DOES THE EUROPEAN MODEL. BY THURSDAY...AN UPPER TROF DIGGING ALONG THE WEST COAST WILL CAUSE A SOUTHWEST FLOW ALOFT TO BRING MOISTURE AND INSTABILITY TO THE AREA AND THE POSSIBILITY OF ISOLATED RAIN AND/OR SNOW SHOWERS. AN INCREASING SOUTHWEST FLOW ALOFT ON FRIDAY WILL SET UP AN OVERRUNNING SITUATION WITH SCATTERED SNOW DEVELOPING. THE BROAD UPPER TROF MOVES TO THE PACIFIC NORTHWEST ON SATURDAY. THE OVERRUNNING SOUTHWEST FLOW ALOFT WILL INTERACT WITH A SURFACE COLD FRONT MOVING SOUTH OUT OF CANADA ON SATURDAY RESULTING IN SCATTERED SNOW DEVELOPING OVER MOST OF THE COUNTY WARNING AREA. TEMPERATURES WILL REMAIN BELOW SEASONAL AVERAGES WITH AFTERNOON HIGH TEMPERATURES BY THE END OF THE PERIOD LIKELY IN THE TEENS. && .AVIATION... UPDATED 2335Z. A MOIST NORTHWESTERLY FLOW ALOFT WILL PREVAIL ACROSS THE REGION THROUGH LATE SUNDAY AFTERNOON. PERSISTENT DOWNSLOPE PRESSURE GRADIENTS WILL ALLOW GUSTY WEST TO SOUTHWEST WINDS TO CONTINUE ACROSS THE FORECAST AREA THIS PERIOD. BROKEN TO OVERCAST MID LEVEL CLOUDS ARE EXPECTED ALONG WITH SCATTERED SNOW SHOWERS AT TIMES. VFR CONDITIONS WILL PREVAIL WITH AREAS IFR/MVFR IN PRECIPITATION. MOUNTAINS WILL BE OBSCURED. MPJ && .PRELIMINARY POINT TEMPS/POPS... GTF 29 43 29 35 / 40 20 50 50 CTB 27 41 26 33 / 20 20 50 50 HLN 26 42 25 36 / 40 40 50 50 BZN 21 41 21 35 / 30 30 50 50 WEY 12 30 13 28 / 60 60 40 60 DLN 20 38 18 35 / 40 50 50 50 HVR 29 45 27 36 / 20 20 50 40 LWT 27 41 26 34 / 30 20 30 50 && .TFX WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING FROM 11 PM THIS EVENING TO 5 PM MST SUNDAY NORTHERN ROCKY MOUNTAIN FRONT...SOUTHERN ROCKY MOUNTAIN FRONT. && SHORT TERM...WARANAUSKAS LONG TERM...EMANUEL AVIATION...MPJ WEATHER.GOV/GREATFALLS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 322 PM MST SAT NOV 12 2011 MTZ008-010>015-044>047-049>055-132230- BEAVERHEAD-EASTERN GLACIER-HILL-CASCADE-CHOUTEAU- CENTRAL AND SOUTHERN LEWIS AND CLARK-MADISON-TOOLE-LIBERTY- EASTERN PONDERA-BLAINE-EASTERN TETON-JUDITH BASIN-FERGUS- JEFFERSON-BROADWATER-MEAGHER-GALLATIN- 322 PM MST SAT NOV 12 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER TONIGHT IS LOW. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY VERY WINDY CONDITIONS WILL DEVELOP SUNDAY AND PERSIST THROUGH MONDAY. ANOTHER WEATHER SYSTEM IN AN UNSETTLED NORTHWEST FLOW ALOFT WILL BRING A CHANCE FOR SNOW ON MONDAY. A MUCH COLDER AIRMASS WILL MOVE INTO THE REGION LATE NEXT WEEK WITH INCREASING CHANCES FOR SNOW NEXT WEEKEND. .SPOTTER INFORMATION STATEMENT... REPORTS OF STRONG WINDS OR WIND DAMAGE WOULD BE GREATLY APPRECIATED. MTZ009-048-132230- NORTHERN ROCKY MOUNTAIN FRONT-SOUTHERN ROCKY MOUNTAIN FRONT- 322 PM MST SAT NOV 12 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT STRONG WEST WINDS WILL REDEVELOP TONIGHT AND A HIGH WIND WARNING IS IN EFFECT FROM TONIGHT THROUGH SUNDAY. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY A HIGH WIND WARNING REMAINS IN EFFECT THROUGH SUNDAY AND VERY WINDY CONDITIONS MAY PERSIST THROUGH MONDAY. ANOTHER WEATHER SYSTEM IN AN UNSETTLED NORTHWEST FLOW ALOFT WILL BRING A CHANCE FOR SNOW ON MONDAY. A MUCH COLDER AIRMASS WILL MOVE INTO THE REGION LATE NEXT WEEK WITH INCREASING CHANCES FOR SNOW NEXT WEEKEND. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS REQUIRED FOR TONIGHT THROUGH SUNDAY. REPORTS OF STRONG WINDS OR WIND DAMAGE WOULD BE GREATLY APPRECIATED.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
429 PM MST SAT NOV 12 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0230 PM SNOW 10 SSE NEIHART 46.79N 110.68W
11/12/2011 M4.0 INCH MEAGHER MT MESONET
LAST 12 HOURS AT THE 6500 FT LEVEL
&&
WILLIAMSONPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
433 PM MST SAT NOV 12 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0230 PM HEAVY SNOW 11 S WEST YELLOWSTONE 44.51N 111.11W
11/12/2011 M9.0 INCH GALLATIN MT MESONET
SNOW FELL LAST 12 HOURS AT BLACK BEAR SNOTEL AT THE
7900 FT LEVEL
&&
WILLIAMSONPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
436 PM MST SAT NOV 12 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0230 PM SNOW 21 S BIG SKY 44.96N 111.29W
11/12/2011 M7.0 INCH GALLATIN MT MESONET
SNOW FELL THE LAST 12 HOURS AT 7000 FT LEVEL
&&
WILLIAMSONPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
438 PM MST SAT NOV 12 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0230 PM SNOW 13 ESE GALLATIN GATEWAY 45.50N 110.97W
11/12/2011 M7.0 INCH GALLATIN MT MESONET
12 HOURS SNOWFALL. EL 6860 FT
&&
WILLIAMSONPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
440 PM MST SAT NOV 12 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0230 PM SNOW 5 S WEST YELLOWSTONE 44.59N 111.12W
11/12/2011 M7.0 INCH GALLATIN MT MESONET
12 HR SNOWFALL. ELE 7750 FT
&&
WILLIAMSONPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
446 PM MST SAT NOV 12 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0400 PM SNOW 5 SW BOZEMAN 45.63N 111.12W
11/12/2011 E4.0 INCH GALLATIN MT TRAINED SPOTTER
12 HOUR SNOWFALL TOTAL. SNOW HAS STOPPED.
&&
MPJ4 high wind. Local standard time, as filed.
A wind gust to 65 mph was reported at Bynum 14W (the Dellwo MSCN site).
A wind gust to 68 mph was reported at the Heart Butte RAWS site.
A wind gust to 64 mph was reported at Cascade 4S.
A wind gust to 61 mph was reported at Townsend 3WNW (the Ginger RAWS site).
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, November 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: 352156, 352154, 352155, 352157.