Strong westerly winds aloft mixed down to the surface and resulted in high winds along the Northern Rocky Mountain Front. Wind gusts in excess of 70 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.
Strong westerly winds aloft mixed down to the surface and resulted in high winds along the Northern Rocky Mountain Front. Wind gusts in excess of 70 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 Sep 25, 9:50 PM MST, 10 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 1050 PM MDT SUN SEP 25 2011 UPDATED AVIATION SECTION .UPDATE... A COLD FRONT IS PASSING THROUGH THE AREA THIS EVENING AND HAS MOVED THROUGH THE GREAT FALLS...HELENA AND FORT BENTON AREAS AS OF 9 PM. IT WILL CONTINUE TO MOVE THROUGH THE REGION OVERNIGHT BRINGING IN COOLER AIR. A FEW LIGHT SHOWERS EARLIER WERE NOT QUITE MAKING IT TO THE GROUND IN THE DRY AIR. LITTLE IF ANY CONTINUED SHOWER ACTIVITY IS EXPECTED OVERNIGHT OVER THE PLAINS. THE BETTER CHANCES WILL REMAIN ALONG THE WESTERN MOUNTAINS. DID DROP THE RED FLAG WARNING AS CRITICAL FIRE CONDITIONS HAVE IMPROVED WITH HIGHER HUMIDITIES AND SOMEWHAT LIGHTER WINDS. DB && .AVIATION... UPDATED 0450Z. EXPECT VFR CONDITIONS. A WEATHER DISTURBANCE ALOFT WILL MOVE EAST THROUGH THE AREA MONDAY MORNING. THIS WILL RESULT IN SKIES BECOMING CLEAR TO SCATTERED CLOUDS BEHIND THE DISTURBANCE. AHEAD OF THE DISTURBANCE EXPECT VFR CONDITIONS. THERE COULD BE A FEW SHOWERS OVER SOUTHWEST MONTANA WITH CEILINGS LOWERING POSSIBLY TO NEAR 6000 FT. OTHERWISE EXPECT CEILINGS AT OR ABOVE 15000 FT MSL. CONFIDENCE IN FORECAST WIND DIRECTIONS THE REST OF TONIGHT IS LOW EXCEPT AT KCTB. FOR MONDAY AFTERNOON STILL EXPECT WESTERLY WINDS 10 TO 20 KNOTS OVER THE NORTHERN EAST SLOPES OF THE ROCKY MOUNTAINS AND EXTENDING TO NORTH CENTRAL MONTANA. BLANK && .PREV DISCUSSION... /ISSUED 520 PM MDT SUN SEP 25 2011/ TONIGHT THROUGH TUESDAY...AN UPPER LEVEL LOW PRESSURE TROF OVER THE WEST COAST WILL MOVE THROUGH THE PACIFIC NORTHWEST TONIGHT AND APPROACH THE ROCKIES BY MORNING. AN ASSOCIATED COLD FRONT...CURRENTLY MOVING OVER THE ROCKIES...WILL MOVE INTO THE EASTERN ZONES BY MIDNIGHT. MODELS HAVE RECENTLY DEVELOPED MORE DYNAMICS WITH THIS TROF BUT IT WILL BE FAST MOVING...AND PRECIP SHOULD REMAIN LOW. WINDS WILL BE STRONG AND GUSTY DURING FRONTAL PASSAGE...AND REMAIN BREEZY BEHIND THE FRONT. SOME MID LEVEL INSTABILITY WILL BE PRESENT DURING THE FRONTAL PASSAGE BUT ANY CONVECTIVE DEVELOPMENT WOULD BE HIGH BASED SHOWERS OR THUNDERSTORMS AND LOWER LEVELS WILL REMAIN QUITE DRY. MID LEVEL WINDS WILL INCREASE BEHIND THE TROF...AND BY TUESDAY WILL BE CONSISTENTLY IN THE 30-40 KT RANGE. BRISK SURFACE WINDS AND AFTERNOON GUSTINESS ON TUESDAY WILL AFFECT MOST OF NORTH CENTRAL MONTANA. ZELZER TUESDAY NIGHT THROUGH SUNDAY NIGHT...MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT WITH THE OVERALL PATTERN...ALTHOUGH SOME DETAILS DIFFER TOWARD THE END OF THE PERIOD. DISTURBANCES IN THE WESTERLY FLOW ALOFT WILL ACT TO FLATTEN THE UPPER LEVEL RIDGE OF HIGH PRESSURE TUESDAY NIGHT INTO WEDNESDAY...WHICH WILL IN TURN KEEP THE FLOW ALOFT QUITE STRONG. WESTERLY SURFACE WINDS WILL REMAIN QUITE BREEZY TUESDAY EVENING AHEAD OF A WEAK CANADIAN COLD FRONT...BUT THIS COLD FRONT WILL THEN MOVE THROUGH NORTHERN MONTANA OVERNIGHT...SHIFTING WINDS MORE NORTHERLY AND DECREASING THEM. THE FRONT WILL ALSO BRING A CHANCE OF SHOWERS TO THE WESTERN MOUNTAINS...A SLIGHT CHANCE OF SHOWERS TO PORTIONS OF CENTRAL MONTANA ALONG THE FRONT...AND 10-15 DEGREE COOLER HIGHS FOR WEDNESDAY OVER TUESDAY. THE UPPER LEVEL RIDGE WILL THEN REBUILD INTO MONTANA WEDNESDAY NIGHT INTO THURSDAY EVENING FOR GENERALLY DRY CONDITIONS. HOWEVER...TEMPERATURES WILL BE SLOW TO WARM BACK UP...AS THE SURFACE HIGH PRESSURE FROM CANADA THAT WILL MOVE IN BEHIND THE COLD FRONT WILL BE SLOW TO EXIT THE AREA. ANOTHER SHORTWAVE TROUGH WILL MOVE INTO THE PACIFIC NORTHWEST TOWARDS THE WEEKEND...BUT THE TIMING OF THIS FEATURE IS WHERE THE MODELS BEGIN TO DIFFER. THE ECMWF BRINGS THE SHORTWAVE THROUGH THE AREA FRIDAY NIGHT THROUGH SATURDAY...WHILE THE GFS MOVES IT THROUGH SATURDAY THROUGH SATURDAY NIGHT. HAVE THEREFORE GONE WITH SLIGHTLY LESS THAN CLIMATOLOGICAL POPS FOR THE FRIDAY NIGHT THROUGH SATURDAY NIGHT PERIOD. WENT SLIGHTLY LESS DUE TO THE OVERALL WEAK NATURE OF THE SHORTWAVE AND GENERAL LACK OF MOISTURE. TEMPERATURES WILL LIKELY WARM BACK UP TO 5 TO 10 DEGREES ABOVE SEASONAL AVERAGES AHEAD OF THIS SYSTEM...BUT THEN COOL BACK CLOSER TO NORMAL WITH ITS PASSAGE. COULSTON && .PRELIMINARY POINT TEMPS/POPS... GTF 50 74 48 80 / 10 10 10 10 CTB 45 68 46 73 / 10 10 10 10 HLN 50 75 46 80 / 20 20 10 10 BZN 44 74 41 80 / 10 20 10 10 WEY 34 64 29 67 / 10 10 10 0 DLN 46 72 41 77 / 30 10 10 10 HVR 49 74 45 83 / 10 10 10 0 LWT 46 71 44 80 / 10 10 10 10 && .TFX WATCHES/WARNINGS/ADVISORIES...NONE. && WEATHER.GOV/GREATFALLS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 939 PM MDT SUN SEP 25 2011 MTZ009-048-270345- NORTHERN ROCKY MOUNTAIN FRONT-SOUTHERN ROCKY MOUNTAIN FRONT- 939 PM MDT SUN SEP 25 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL MONTANA. .DAY ONE...TONIGHT THERE IS A LOW PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THERE IS A THREAT OF HIGH WINDS MONDAY NIGHT THROUGH TUESDAY NIGHT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. MTZ008-010>015-044>047-049>055-270345- 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- 939 PM MDT SUN SEP 25 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...TONIGHT THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
3 high wind. Local standard time, as filed.
A wind gust to 79 mph was reported at Saint Mary 13W (the Logan Pass Visitor Center in Glacier National Park).
A wind gust to 72 mph was reported at Saint Mary 13W (the Logan Pass Visitor Center in Glacier National Park).
A wind gust to 64 mph was reported at East Glacier Park 8SE (the Deep Creek 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, September 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: 346383, 346381, 346382.