A Pacific storm brought heavy snow to portions of Southwest Montana. Snow accumulations of more than 12 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 brought heavy snow to portions of Southwest Montana. Snow accumulations of more than 12 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 May 22, 10:30 AM MST, 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 1130 AM MDT SAT MAY 22 2010 .UPDATE FOR AVIATION... THE UPPER LEVEL LOW REMAINS SLIGHTLY WEST OF THE REGION. MAJORITY OF PRECIP IS CURRENTLY ASSOCIATED WITH UPSLOPE FLOW ACROSS THE PLAINS. THE MODELS BRING DRIER AIR INTO THE AREA FROM THE NORTHWEST DURING THE DAY BUT WIDESPREAD PRECIP WILL CONTINUE...WITH THE SOUTHWEST AND NORTHEAST ZONES REMAINING THE WETTEST. WILL FRESHEN POPS AND LOWER MOST TEMPS A BIT. ZELZER && .AVIATION... UPDATED 1200Z UPPER LEVEL TROUGH CONTINUES TO BRING A MOIST AND UNSTABLE SOUTHERLY FLOW ALOFT INTO CENTRAL MT LATER TODAY AND TONIGHT WHILE SURFACE LOW TRACKS FARTHER EAST FROM WY INTO THE DAKOTAS. MVFR CONDITIONS AND WIDESPREAD MTN OBSCURATION IN SHOWERS WILL PREVAIL THROUGH MUCH OF THIS AFTERNOON AND TONIGHT WITH LOCAL IFR CONDITIONS IN HEAVIER PRECIPITATION AND AREAS OF MIXED PRECIPITATION OR SNOW. SNOW LEVELS WILL FLUCTUATE AROUND 5000 FT MSL THROUGH MUCH OF TODAY...LOWERING TO AROUND 4000 FT TONIGHT. SURFACE WINDS WILL INCREASE FROM THE NW OVER NORTH CENTRAL MT TERMINALS AS DEEPENING LOW PRESSURE TRACKS NE INTO EASTERN MT THIS AFTERNOON AND EVENING. WILLIAMSON DC && .HYDROLOGY... PORTIONS OF NORTHCENTRAL MONTANA ARE UNDER A FLOOD WARNING. MANY STREAMS ARE ALREADY OUT OF THEIR BANKS AND WIDESPREAD PRECIPITATION IS EXPECTED TO CONTINUE THROUGH THE WEEKEND. RUN-OFF FROM SNOWMELT AND EXPECTED RAINFALL WILL IMPACT CREEKS AND STREAMS THAT ARE ALREADY RUNNING HIGH AND A SMALL STREAM FLOOD ADVISORY REMAINS IN EFFECT FOR PORTIONS OF NORTH CENTRAL AND CENTRAL MONTANA. WITH FORECASTED PRECIPITATION AMOUNTS GENERALLY IN THE ONE-HALF INCH RANGE...COOLER TEMPERATURES FORECAST THROUGH THE WEEKEND...AND RIVER FORECAST CENTER ESTIMATES...FURTHER HIGHLIGHTS ARE NOT ANTICIPATED. && .PREV DISCUSSION... /ISSUED 555 AM MDT SAT MAY 22 2010/ TODAY THROUGH MONDAY...VERY MOIST AND UNSETTLED PATTERN WILL CONTINUE THROUGH THE WEEKEND AND INTO EARLY NEST WEEK. A BROAD UPPER TROF CONTINUES TO MOVE SLOWLY OVER THE AREA. SHORT WAVE ENERGY WILL CONTINUE TO ROTATE OUT FROM THE BASE OF THE TROF AND MOVE NORTH AND EAST ACROSS THE AREA. WIDESPREAD RAIN WILL BE THE RESULT TODAY. AN ISOLATED THUNDERSTORM IS ALSO POSSIBLE EARLY THIS MORNING OVER THE EASTERN PORTION OF THE COUNTY WARNING AREA. AS THE UPPER LOW MOVES OVER SASKATCHEWAN TONIGHT...THE RETURN CIRCULATION OVER NORTHERN MONTANA WILL BRING ADDITIONAL PRECIPITATION. SOME SNOW IS LIKELY TONIGHT OVER THE PLAINS BUT AMOUNTS WILL BE ON THE LIGHT SIDE. MODELS CONTINUE TO INDICATE A LACK OF VERY COLD AIR ASSOCIATED WITH THE PASSAGE OF THE UPPER LOW. PRECIPITATION WILL DECREASE ACROSS THE NORTH ON SUNDAY BUT INCREASE OVER THE SOUTH AND SOUTHWEST AS ANOTHER LOBE OF ENERGY BEGINS TO MOVE TOWARD THE AREA. ANOTHER WIDESPREAD PRECIPITATION EVENT WILL OCCUR MONDAY AS THE NEXT SHORT WAVE MOVES THROUGH. TEMPERATURES WILL CONTINUE WELL BELOW SEASONAL AVERAGES. EMANUEL MONDAY NIGHT THROUGH SATURDAY...MEDIUM RANGE MODELS REMAIN IN FAIR AGREEMENT THROUGH THE MIDDLE OF NEXT WEEK. A VIGOROUS UPPER LEVEL LOW LIFTS NORTHEAST ACROSS CENTRAL AND EASTERN MT MONDAY NIGHT FOR WIDESPREAD PRECIPITATION WITH FOCUS FOR HIGHEST PRECIPITATION AMOUNTS EXPECTED TO BE OVER NORTH CENTRAL MT AS MOISTURE WRAPS AROUND DEEPENING LOW PRESSURE MONDAY NIGHT. UPPER LOW LIFTS N INTO CANADA TUESDAY WITH BROAD TROUGHING REMAINING OVER THE REGION UNDER A MOIST SOUTHERN FLOW ALOFT WITH THE MAIN UPPER TROUGH AXIS VERY SLOWLY APPROACHING THE COAST THROUGH THE SECOND HALF OF NEXT WEEK BEFORE THE ENTIRE TOUGH MOVES INLAND NEXT WEEKEND. PRECIPITATION WILL DIMINISH FROM SW TO NE BEHIND THE EXITING LOW TUESDAY AFTERNOON...FOLLOWED BY A BRIEF PERIOD OF DRYING TUESDAY NIGHT THROUGH EARLY WEDNESDAY. SOUTH TO SOUTHWEST FLOW ALOFT AHEAD OF THE APPROACHING TROUGH WILL BRING A CHANCE FOR SHOWERS AND POSSIBLY SOME THUNDERSTORMS LATE WEDNESDAY INTO NEXT WEEKEND AS THE NEXT UPPER LEVEL TROUGH SLOWLY APPROACHES. SLIGHTLY BELOW AVERAGE TEMPERATURES TUESDAY WARM BACK TO NEAR SEASONAL AVERAGES BY WEDNESDAY AND CONTINUE THROUGH THE REMAINDER OF NEXT WEEK. HOENISCH && .PRELIMINARY POINT TEMPS/POPS... GTF 45 36 57 36 / 100 80 40 40 CTB 48 32 55 34 / 80 70 40 20 HLN 48 35 59 37 / 90 80 50 60 BZN 47 32 59 38 / 90 60 50 60 WEY 41 21 48 28 / 60 50 50 70 DLN 44 28 51 36 / 80 80 50 70 HVR 44 39 58 40 / 100 80 40 20 LWT 43 32 54 37 / 100 60 40 60 && .TFX WATCHES/WARNINGS/ADVISORIES... FLOOD WARNING FOR PORTIONS OF NORTH CENTRAL MONTANA THROUGH SUNDAY. FLOOD ADVISORY FOR PORTIONS OF NORTH CENTRAL MONTANA THROUGH MONDAY. && WEATHER.GOV/GREATFALLS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 551 AM MDT SAT MAY 22 2010 MTZ012-013-050-051-231200- CASCADE-CHOUTEAU-JUDITH BASIN-FERGUS- 551 AM MDT SAT MAY 22 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA AND NORTH CENTRAL MONTANA. .DAY ONE...TODAY AND TONIGHT A FLOOD WARNING FOR RAIN AND SNOWMELT IS IN EFFECT FOR SMALL STREAMS. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY THE FLOOD WARNING FOR RAIN AND SNOWMELT REMAINS IN EFFECT FOR SMALL STREAMS UNTIL 10 AM MDT SUNDAY. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. MTZ011-014-044-045-047-054-231200- HILL-CENTRAL AND SOUTHERN LEWIS AND CLARK-TOOLE-LIBERTY-BLAINE- MEAGHER- 551 AM MDT SAT MAY 22 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT A SMALL STREAM FLOOD ADVISORY FOR RAIN AND SNOWMELT IS IN EFFECT. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY THE SMALL STREAM FLLOD ADVISORY FOR RAIN AND SNOWMELT REMAINS IN EFFECT UNTIL 1015 AM MDT MONDAY. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. MTZ008>010-015-046-048-049-052-053-055-231200- BEAVERHEAD-NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER-MADISON- EASTERN PONDERA-SOUTHERN ROCKY MOUNTAIN FRONT-EASTERN TETON- JEFFERSON-BROADWATER-GALLATIN- 551 AM MDT SAT MAY 22 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY 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.
1 winter storm. Local standard time, as filed.
Fifteen inches of snow fell at Jackson 14S (the Bloody Dick SNOTEL site - elevation 7549 feet). Sixteen inches of snow fell at Jackson 19S (the Lemhi Ridge SNOTEL site - elevation 8100 feet).
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, May 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: 222742.