The flooding of Spring Creek caused road closures in the area.
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.
The flooding of Spring Creek caused road closures in the area.
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, 4:03 AM MST, 4 hours earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 503 AM MDT SUN MAY 22 2011 .DISCUSSION... TODAY THROUGH TUESDAY...THE WEATHER SYSTEM THAT BROUGHT PRECIPITATION TO MOST OF THE AREA OVER THE LAST COUPLE OF DAYS WILL CONTINUE TO MOVE EAST OUT OF THE AREA TODAY. THIS WILL ALLOW LINGERING PRECIPITATION TO DECREASE EAST OF A CUT BANK TO GREAT FALLS LINE. HOWEVER...ANOTHER WEATHER SYSTEM WILL MOVE INTO THE PACIFIC NORTHWEST TODAY AND TONIGHT...THEN IT WILL SLOWLY MOVE SOUTHEAST INTO THE NORTHERN GREAT BASIN MONDAY THROUGH TUESDAY. THE RESULTING MOIST AND UNSTABLE SOUTHERLY FLOW ALOFT WILL BRING PERIODS OF SHOWERS WITH POSSIBLE AFTERNOON/EVENING THUNDERSTORMS TO MOST OF THE AREA THROUGH THE PERIOD. THE SOUTHERLY FLOW ALOFT WILL ALSO HELP WARM TEMPERATURES ACROSS THE AREA...BUT EXTENSIVE CLOUD COVER AND SHOWERS WILL KEEP TEMPERATURES FROM WARMING TOO MUCH. THE END RESULT WILL BE SLIGHTLY COOLER THAN NORMAL HIGH TEMPERATURES AND SLIGHTLY WARMER THAN NORMAL OVERNIGHT LOWS. THE ADDITIONAL RAINFALL AND CONTINUED SNOWMELT OUT OF THE MOUNTAINS WILL CAUSE CONTINUE FLOODING CONCERNS. PLEASE SEE DETAILS IN THE HYDROLOGY SECTION. COULSTON TUESDAY NIGHT THROUGH SUNDAY...MODELS ARE IN FAIRLY CLOSE AGREEMENT THROUGH THURSDAY. WITH THE FLOW GENERALLY STAGNANT ACROSS THE AREA...SOME UPSLOPE PRECIPITATION SHOULD CONTINUE ALONG THE ROCKY MOUNTAIN FRONT AND ACROSS MUCH OF CENTRAL AND SOUTHWEST MONTANA. NORTH CENTRAL PORTIONS WILL BE THE ONLY AREA MOSTLY DRY. THIS PATTERN WILL CONTINUE ON WEDNESDAY WITH SOME WEAK RIDGING EXPECTED. SHOULD SEE SOME PULL-BACK WESTWARD OF THE PRECIPITATION CHANCES REMAINING IN THE CHANCE CATEGORY ACROSS THE WESTERN MOUNTAINS AND ADJACENT PLAINS ON THURSDAY...AS A NEW WEATHER SYSTEM ADVANCES TO THE NORTHERN ROCKIES. AS THIS SYSTEM PROGRESSES ACROSS MONTANA ON THURSDAY...WILL AGAIN SPREAD CHANCE PRECIP PROBABILITIES ACROSS THE CWA...DIMINISHING LATER ON THURSDAY. MODEL DIFFERENCES INCREASE ON FRIDAY WHILE A RIDGE IS EXPECTED TO DEVELOP ACROSS AND FURTHER DRY OUT THE AREA. MEANWHILE...THE ECMWF BRINGS A WEAK UPPER LOW ACROSS MONTANA...SO WILL KEEPS PRECIP PROBABILITIES NEAR CLIMATOLOGICAL MEANS. ON SATURDAY AND SUNDAY...MODELS BUILD A RIDGE ACROSS THE REGION. THE ENSEMBLES ARE IN AGREEMENT THROUGH THURSDAY...THEN SOME SPREAD DEVELOPS. THOUGH MORE SPREAD IN THE SOLUTIONS DEVELOPS BY FRIDAY THROUGH SUNDAY...THERE IS CONSENSUS IN BUILDING A RIDGE OVER MONTANA...BUT THE STRENGTH OF THE RIDGE VARIES. DB && .AVIATION... UPDATED 1055Z. PERIODS OF RAIN...MODERATE TIMES...WILL CONTINUE TO FALL IN THE GREAT FALLS/HAVRE/LEWISTOWN AREAS THROUGH THIS MORNING. ISOLATED SHOWERS WILL BE POSSIBLE ELSEWHERE. EXPECT MOUNTAINS TO BE OBSCURED AT TIMES THIS MORNING. SOME DRIER AIR MOVES INTO THE AREA BY LATE SUNDAY MORNING...BUT THE AIRMASS BECOMES UNSTABLE BY MID AFTERNOON...WITH A FEW SHOWERS/ISOLATED THUNDERSTORMS POSSIBLE OVER CENTRAL AND SOUTHWEST MONTANA FROM THE AFTERNOON THROUGH THE EVENING HOURS. SKIES WILL REMAIN MOSTLY CLOUDY OVERNIGHT AS SHOWERS END THIS EVENING. DB && .HYDROLOGY... FLOOD WARNINGS CONTINUE FOR FERGUS...JUDITH BASIN...CHOUTEAU AND CASCADE COUNTIES WHERE NUMEROUS REPORTS HAVE BEEN RECEIVED OF ROADWAYS BEING AFFECTED BY HIGH WATER. ONE LOCATION OF NOTE IS THE MISSOURI RIVER NEAR LANDUSKY IN FERGUS COUNTY. IT HAS EXCEEDED FLOOD STAGE OVERNIGHT AND IS LIKELY AFFECTING THE JAMES KIPP STATE PARK. THE MBRFC HAS ISSUED A SPECIAL FORECAST FOR THIS SITE AND THE INFORMATION WILL BE INCLUDED IN THE WARNING STATEMENT. IN ADDITION...A FLOOD WARNING CONTINUES FOR SOUTHERN BLAINE COUNTY WHERE REPORTS OF FLOODING ALONG PEOPLES CREEK NEAR HAYS AND LODGE POLE HAVE BEEN RECEIVED. WHILE PRECIPITATION WILL GRADUALLY DIMINISH IN THESE AREAS TODAY...MELTING SNOWPACK DELAYED RAINFALL RUNOFF WILL LIKELY CONTINUE TO KEEP AREA STREAMS AT ELEVATED LEVELS WITH ADDITIONAL RISES STILL POSSIBLE THROUGH AT LEAST MONDAY. A FLOOD WATCH FOR THE GALLATIN RIVER NEAR LOGAN REMAINS IN EFFECT UNTIL FURTHER NOTICE. THE LATEST MBRFC FORECAST HAS THIS SITE EXCEEDING FLOOD STAGE LATE THIS AFTERNOON...HOWEVER THE RIVER SEEMS TO BE LEVELING OFF AS OF THIS MORNING. THIS MAY ONLY BE TEMPORARY AND THE SITUATION WILL CONTINUE TO BE MONITORED FOR A POSSIBLE FLOOD WARNING. A SMALL STREAM FLOOD ADVISORY ALSO REMAINS IN EFFECT FOR PORTIONS OF GALLATIN COUNTY THROUGH AT LEAST MONDAY EVENING. ROCKS ARE CAUSING AN OBSTRUCTION IN A CULVERT ALONG US HIGHWAY 191 BETWEEN BOZEMAN AND BIG SKY. THIS HAS CAUSED WATER FROM SNOWMELT AND RAINFALL RUNOFF TO RUN OVER THE ROAD...AND COUNTY OFFICIALS HAVE CLOSED THAT PORTION OF THE ROAD. THEREFORE...THE ADVISORY WILL LIKELY REMAIN IN EFFECT UNTIL THE OBSTRUCTION CAN BE CLEARED AND THE ROAD IS RE-OPENED. THE FLOOD WATCH FOR HILL AND MEAGHER COUNTIES HAS BEEN EXPANDED TO INCLUDE THE REMAINDER OF THE TFX CWA NOT INCLUDED IN THE ABOVE WARNINGS...ADVISORIES...AND WATCHES. SHOWERS WILL LIKELY INCREASE ACROSS THE ENTIRE AREA THIS AFTERNOON AND PERIODS OF SHOWERS WITH POSSIBLE AFTERNOON/EVENING THUNDERSTORMS WILL LIKELY PRODUCE A TOTAL OF AROUND ONE HALF INCH OF PRECIPITATION AT LOWER ELEVATIONS AND UP TO ONE INCH IN THE MOUNTAINS. THE SNOWPACK IS STILL QUITE SIGNIFICANT IN SOUTHWEST MONTANA AND SOILS ARE GENERALLY VERY MOIST. MANY RIVERS...CREEKS...AND STREAMS ARE ALREADY RUNNING QUITE HIGH AND ANY ADDITIONAL SNOWMELT AND/OR RAINFALL RUNOFF MAY CAUSE THEM TO SWELL EVEN MORE OR POTENTIALLY CAUSE THEM TO FLOW OUT OF THEIR BANKS. WILL CONTINUE TO MONITOR THIS SITUATION CLOSELY FOR POTENTIAL ADVISORIES OR WARNINGS ACROSS THIS AREA. && .PRELIMINARY POINT TEMPS/POPS... GTF 65 45 66 45 / 70 60 50 60 CTB 64 43 66 42 / 80 60 50 60 HLN 65 44 67 44 / 70 50 50 60 BZN 66 42 66 42 / 60 50 50 60 WEY 54 35 55 33 / 60 60 60 60 DLN 63 39 61 39 / 60 50 60 60 HVR 64 48 65 45 / 90 60 30 30 LWT 59 43 62 43 / 90 50 40 60 && .TFX WATCHES/WARNINGS/ADVISORIES... FLOOD WARNINGS THROUGH MID AFTERNOON MONDAY FOR CASCADE...FERGUS...JUDITH BASIN...CHOUTEAU AND BLAINE COUNTIES. SMALL STREAM FLOOD ADVISORY UNTIL MONDAY EVENING FOR PORTIONS OF GALLATIN COUNTY. FLOOD WATCH FOR THE GALLATIN RIVER NEAR LOGAN IN GALLATIN COUNTY UNTIL FURTHER NOTICE. FLOOD WATCH UNTIL FURTHER NOTICE BEAVERHEAD...BROADWATER... CENTRAL AND SOUTHERN LEWIS AND CLARK...EASTERN GLACIER...EASTERN PONDERA...EASTERN TETON...HILL...JEFFERSON...LIBERTY...MADISON... MEAGHER...NORTHERN ROCKY MOUNTAIN FRONT...SOUTHERN ROCKY MOUNTAIN FRONT...TOOLE. && SHORT TERM...COULSTON LONG TERM...DB AVIATION...DB WEATHER.GOV/GREATFALLS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 836 AM MDT SUN MAY 22 2011 MTZ008>015-044>055-231445- 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- 836 AM MDT SUN MAY 22 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT A FLOOD WARNING IS IN EFFECT FOR BLAINE...CASCADE...CHOUTEAU... FERGUS...JUDITH BASIN...AND MEAGHER COUNTIES. A SMALL STREAM FLOOD ADVISORY IS IN EFFECT FOR GALLATIN COUNTY...AND A POINT FLOOD WATCH IS IN EFFECT SPECIFICALLY FOR THE GALLATIN RIVER NEAR LOGAN IN GALLATIN COUNTY. AN AREAL FLOOD WATCH IS ALSO IN EFFECT FOR THE REMAINDER OF NORTH CENTRAL...CENTRAL...AND SOUTHWEST MONTANA NOT MENTIONED ABOVE. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THE FLOOD WARNING IS IN EFFECT UNTIL AT LEAST TUESDAY MORNING. THE SMALL STREAM FLOOD ADVISORY IS IN EFFECT UNTIL AT LEAST MONDAY EVENING...WHILE THE POINT FLOOD WATCH IS IN EFFECT UNTIL FURTHER NOTICE. THE AREAL FLOOD WATCH IS IN EFFECT UNTIL FURTHER NOTICE. WHILE PRECIPITATION ACROSS NORTH CENTRAL AND CENTRAL MONTANA WILL EXIT THE AREA TODAY...ANOTHER WEATHER SYSTEM WILL BRING PERIODS OF SHOWERS TO MOST OF THE AREA THROUGH TUESDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS REQUESTED ALONG ALL CREEKS AND RIVERS. REPORTS OF FLOODING WOULD BE GREATLY APPRECIATED.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
727 AM MDT SUN MAY 22 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0700 AM HEAVY RAIN FORT BELKNAP 48.48N 108.77W
05/22/2011 M2.95 INCH BLAINE MT TRAINED SPOTTER
TOTAL RAINFALL SINCE WEDNESDAY 7AM.
&&
NJLThe national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
Flooding occurred on Spring Creek Road.
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, May 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: 370422.