cold temperatures and instability to Southwest Montana resulting in heavy snowfall. Accumulations in excess of 6 inches 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.
A Pacific storm system brought moisture...cold temperatures and instability to Southwest Montana resulting in heavy snowfall. Accumulations in excess of 6 inches 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 Mar 15, 4:55 AM MST, 5 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 555 AM MDT SUN MAR 15 2009 ...UPDATE TO AVIATION... .DISCUSSION... TODAY THROUGH TUESDAY...A COMPLEX FORECAST IN IN STORE FOR CENTRAL AND SOUTHWEST MONTANA DURING THE SHORT TERM PERIOD. WEATHER FOR TODAY THROUGH MONDAY WILL BE DOMINATED BY A BROAD UPPER LEVEL TROUGH THAT ROTATES INLAND ACROSS THE PACIFIC NORTHWEST. A STRONG JET STREAM WILL NOSE INTO WESTERN MONTANA BRINGING ABUNDANT MOISTURE AND STRONG WINDS TO THE MOUNTAINS OF THE ROCKY MOUNTAIN FRONT TODAY AND TONIGHT. WILL UPGRADE THE CURRENT WINTER STORM WATCH FOR THE ROCKY MOUNTAIN FRONT TO A WARNING...AND WILL ALSO MOVE THE START TIME UP TO 6 AM THIS MORNING AS RADAR MOSAIC IS ALREADY SHOWING PRECIPITATION MOVING ACROSS WESTERN MONTANA. WATCH FOR THE CENTRAL AND SOUTHWEST ZONES IS MORE PROBLEMATIC. MOIST WESTERLY FLOW ALOFT WILL BRING AN INCREASING CHANCE OF PRECIPITATION TO THE MOUNTAINS NEAR YELLOWSTONE PARK TODAY. BY TONIGHT SNOW LEVELS WILL LOWER TO THE VALLEY FLOOR IN THE WEST YELLOWSTONE AREA AND EXPECT SIGNIFICANT ACCUMULATIONS IN THIS AREA OVERNIGHT. HOWEVER...DURING THIS TIME FRAME THE MAJORITY OF SOUTHWEST MONTANA WILL NOT RECEIVE MUCH PRECIPITATION...ESPECIALLY THE VALLEYS WHERE I EXPECT TEMPERATURES TO REMAIN TOO WARM FOR MUCH SNOWFALL. AS THE TROUGH MOVES INTO THE REGION TONIGHT A BAROCLINIC ZONE IS EXPECTED TO SET UP OVER CENTRAL MONTANA WITH A BAND OF ENHANCED PRECIPITATION DEVELOPING SOMEWHERE IN THE HELENA TO GREAT FALLS REGION. THIS BAND WILL SAG SOUTH OVERNIGHT AND THEN STALLS OUT OVER SOUTHWEST MONTANA ON MONDAY BEFORE GRADUALLY DISSIPATING MONDAY NIGHT. DURING THIS TIME FRAME I AM CALCULATING THAT THE AREA MOST LIKELY TO RECEIVE WARNING CRITERIA SNOW ACCUMULATIONS WILL BE THE MOUNTAINS OF SOUTHERN MADISON AND GALLATIN COUNTIES AS WELL AS LOWER ELEVATIONS IN THE WEST YELLOWSTONE AREA. OTHER REGIONS IN THE WATCH AREA WILL RECEIVE LESSER SNOW AMOUNTS...BUT CAN STILL EXPECT RELATIVELY STRONG AND GUSTY WINDS IN THE MOUNTAINS. SINCE MODELS HAVE MADE A FAIRLY SIGNIFICANT CHANGE IN TIMING FOR THIS REGION I WOULD PREFER TO HOLD OFF ON UPGRADING TO A WARNING AT THIS TIME SO THAT DAY SHIFT CAN CHECK OUT ANOTHER MODEL RUN AND MAKE ADDITIONAL TWEAKS IF NECESSARY. SO HAVE INSTEAD DECIDED TO ADJUST THE STARTING TIME FOR THE WATCH BACKWARD TO 6 PM MDT THIS EVENING FOR MY FAR SOUTHWEST ZONES...AND WILL GO WITH A MIDNIGHT MONDAY START TIME FOR THE CENTRAL ZONES. ZONAL FLOW ALOFT CONTINUES ACROSS MONTANA FOR THE REMAINDER OF THE SHORT TERM WITH SHOWERS CONTINUING OVER THE WESTERN MOUNTAINS AND TEMPERATURES REMAINING NEAR OR SLIGHTLY ABOVE SEASONAL AVERAGES. MPJ TUESDAY NIGHT THROUGH FRIDAY NIGHT...MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT THROUGH THURSDAY NIGHT...BUT THEY DIVERGE SOMEWHAT AFTER THEN. A MOIST AND STRONG WESTERLY FLOW ALOFT WILL REMAIN OVER NORTH CENTRAL...CENTRAL...AND SOUTHWEST MONTANA THROUGH AT LEAST THURSDAY NIGHT. EMBEDDED DISTURBANCES IN THE FLOW WILL BRING A CHANCE OF SNOW TO THE MOUNTAINS THROUGH THIS PERIOD...WHILE VALLEY AND PLAINS LOCATIONS WILL ONLY HAVE A SLIGHT CHANCE OF PRECIPITATION AT BEST. WEAK FRONTAL BOUNDARIES WILL ACCOMPANY THE DISTURBANCES...ENHANCING THE SURFACE WINDS AND KEEPING THEM OUT OF THE SOUTHWEST TO WEST. THE STRONGEST WINDS WILL BE ALONG THE EAST SLOPES OF THE ROCKIES. THE GFS AND ECMWF MODELS DIFFER ON THE STRENGTH OF THESE WINDS...WITH THE GFS THE STRONGER OF THE TWO MODELS. THE STRONG WESTERLY FLOW WILL ALSO KEEP TEMPERATURES WELL ABOVE NORMAL DURING THIS TIME...WITH HIGHS IN THE 50S BEING COMMON AT MOST LOWER ELEVATION LOCATIONS. FOR THE FRIDAY AND FRIDAY NIGHT PERIOD...THE GFS CONTINUES THE STRONG WESTERLY FLOW ALOFT SIMILAR TO THE INITIAL PORTION OF THE FORECAST PERIOD...BUT THE ECMWF STARTS BUILDING A STRONG UPPER LEVEL RIDGE OVER THE AREA. THE ECMWF SOLUTION WOULD KEEP THE AREA MUCH DRIER AND WARMER...WHILE THE GFS WOULD CONTINUE THE PATTERN OF MAINLY MOUNTAIN PRECIPITATION AND ONLY MODERATELY WARM TEMPERATURES. WILL CONTINUE WITH THE GENERAL PATTERN OF THE GFS DURING THIS TIME...BUT WILL FURTHER EVALUATE OVER THE NEXT FEW DAYS. COULSTON SATURDAY AND SUNDAY...MODELS SHOW A LONG WAVE UPPER LEVEL TROUGH OVER THE PACIFIC NORTHWEST WITH AN UPPER LEVEL RIDGE OVER THE CENTRAL U.S. THIS IS PRETTY CLOSE AGREEMENT WITH THE MODEL ENSEMBLES. THUS...WILL GO WITH SLIGHTLY COOLER THAN SEASONAL AVERAGE WITH ISOLATED TO SCATTERED RAIN OR SNOW SHOWERS. WILLIAMSON DC && .AVIATION... UPDATED 1155Z. A MOIST SOUTHWESTERLY FLOW ALOFT WILL OBSCURE THE MOUNTAINS OF WESTERN MONTANA IN SNOW THROUGH TONIGHT. SNOW WILL GRADUALLY SPREAD SOUTH THROUGHOUT THE DAY AND OBSCURE THE MOUNTAINS OF SOUTHWEST MONTANA AS WELL. OTHERWISE...A SHORTWAVE TROUGH IN THE FLOW WILL MOVE THROUGH THE AREA TODAY AND TONIGHT. MAINLY MID AND HIGH CLOUDS WILL MOVE OVER THE TERMINALS OF NORTH CENTRAL...CENTRAL...AND SOUTHWEST MONTANA THROUGHOUT THE DAY. SOUTHWEST WINDS WILL INCREASE DURING THE DAY AS WELL AT ALL TERMINALS...WITH THE STRONGEST WINDS OCCURRING ALONG THE EAST SLOPES OF THE ROCKIES WHERE GUSTS COULD REACH 45 KT. WINDS WILL DECREASE SOMEWHAT THIS EVENING. AREAS OF LIGHT PRECIPITATION WITH POSSIBLE MVFR CONDITIONS WILL DEVELOP AT THE NORTHERN PLAINS TERMINALS (KCTB AND KHVR) FIRST LATE THIS AFTERNOON...THEN SPREAD SOUTH TO THE KGTF AND KLWT TERMINALS BY 03Z THIS EVENING. THERE WILL BE A BETTER CHANCE OF PRECIPITATION AND MVFR CONDITIONS AT THE SOUTHWEST VALLEY TERMINALS (KHLN AND KBZN) THROUGHOUT THE EVENING AND OVERNIGHT HOURS. WINDS ACROSS THE PLAINS WILL SHIFT MORE WESTERLY AFTER 05Z IN THE WAKE OF THE SHORTWAVE AND ITS ASSOCIATED FRONTAL BOUNDARY. COULSTON && .PRELIMINARY POINT TEMPS/POPS... GTF 54 28 42 25 / 20 50 30 20 CTB 47 23 39 21 / 20 30 10 10 HLN 56 32 42 26 / 30 70 70 40 BZN 51 35 43 28 / 30 50 80 50 WEY 38 29 34 24 / 90 100 100 80 DLN 45 32 41 27 / 40 60 80 40 HVR 47 24 39 20 / 20 30 10 10 LWT 51 30 40 25 / 20 40 50 40 && .TFX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 AM MDT MONDAY FOR MTZ009-048. WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE MONDAY NIGHT FOR MTZ014-052>054. WINTER STORM WATCH FROM THIS EVENING THROUGH LATE MONDAY NIGHT FOR MTZ008-015-055. && SHORT TERM...MPJ LONG TERM...COULSTON/WILLIAMSON DC AVIATION...COULSTON WEATHER.GOV/GREATFALLS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 522 AM MDT SUN MAR 15 2009 MTZ009-048-161200- NORTHERN ROCKY MOUNTAIN FRONT-SOUTHERN ROCKY MOUNTAIN FRONT- 522 AM MDT SUN MAR 15 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL MONTANA. .DAY ONE...TODAY AND TONIGHT A WINTER STORM WARNING HAS BEEN ISSUED FOR ELEVATIONS ABOVE 5000 FEET INCLUDING MARIAS PASS. SNOW AND STRONG WINDS WILL COMBINE TO CREATE HAZARDOUS WINTER DRIVING CONDITIONS TODAY THROUGH LATE TONIGHT. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY 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. MTZ008-014-015-052>055-161200- BEAVERHEAD-CENTRAL AND SOUTHERN LEWIS AND CLARK-MADISON-JEFFERSON- BROADWATER-MEAGHER-GALLATIN- 522 AM MDT SUN MAR 15 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT A WINTER STORM WATCH IS IN EFFECT FOR ALL OF SOUTHWEST MONTANA BEGINNING TONIGHT. SNOW WILL COMBINE WITH GUSTY WINDS TO PRODUCE DANGEROUS WINTER CONDITIONS...ESPECIALLY IN THE MOUNTAINS AND IN THE WEST YELLOWSTONE AREA. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THE WINTER STORM WATCH REMAINS EFFECT FOR ALL OF SOUTHWEST MONTANA THROUGH MONDAY NIGHT. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. MTZ010>013-044>047-049>051-161200- EASTERN GLACIER-HILL-CASCADE-CHOUTEAU-TOOLE-LIBERTY- EASTERN PONDERA-BLAINE-EASTERN TETON-JUDITH BASIN-FERGUS- 522 AM MDT SUN MAR 15 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA AND NORTH CENTRAL MONTANA. .DAY ONE...TODAY AND 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... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
9 winter storm. Local standard time, as filed.
Ten inches of snow fell at Babb 19W (the Flattop Mountain SNOTEL site - elevation 6300 feet).
Seven inches of snow fell at Bynum 24W (the Waldron SNOTEL site - elevation 5600 feet).
Six inches of snow fell at Helena.
Mountains across the southern portions of the county received over 12 inches of snowfall in the last 24 hours.
Mountains across the southern portions of the county received over 12 inches of snowfall in the last 24 hours.
Seventeen inches of snow fell at White Sulphur Springs.
Six inches of snow fell at Townsend 11ENE.
Estimated 7 inches of new snow fell at 24 W Bynum at the Waldron SNOTEL Site. Elevation is 5600 feet.
Twelve inches of snow fell at Basin.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2009Every state in 2009This day in weather historyWarnings in Montana, March 2009
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: 157874, 157876, 157877, 160938, 160940, 157881, 157879, 160932, 157878.