Flooding due to excessive rainfall and snowmelt caused Belt Creek to become flooded. Flooding emergency declared for Cascade county on 5/23/11.
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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.
Flooding due to excessive rainfall and snowmelt caused Belt Creek to become flooded. Flooding emergency declared for Cascade county on 5/23/11.
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 21, 8:55 AM MST, 4 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 955 AM MDT SAT MAY 21 2011 .UPDATE... RAIN CONTINUES TO AFFECT MUCH OF THE EASTERN PORTION OF THE FORECAST AREA SO WILL CONTINUE WITH THE HIGH CHANCES OF PRECIPITATION THERE. ELSEWHERE RADAR AND OBSERVATIONS ARE NOT SHOWING MUCH PRECIPITATION SO WILL LOWER THE CHANCES OF PRECIPITATION FOR THIS MORNING. ALSO THREAT OF THUNDERSTORMS LOOKS MINIMAL AT BEST FOR TODAY SO HAVE DROPPED THE MENTION OF THEM. BLANK && .AVIATION... UPDATED 1220Z. WIDESPREAD PRECIPITATION WITH MOUNTAIN OBSCURATION WILL CONTINUE AT LEAST THROUGH THIS MORNING ACROSS NORTH CENTRAL...CENTRAL...AND SOUTHWEST MONTANA. THE HEAVIEST PRECIPITATION WITH THE LOWEST CEILINGS/VISIBILITIES WILL BE EAST OF A KCTB-KGTF-KBZN LINE...WHERE CONDITIONS WILL MOSTLY BE MVFR...THOUGH IFR CEILINGS WILL LINGER IN THE KLWT AREA. THE REMAINDER OF THE AREA WILL REMAIN VFR...BUT BANDS OF PRECIPITATION WITH OCCASIONAL MVFR CONDITIONS WILL MOVE WEST THROUGH THE AREA. AFTER 18Z...CONDITIONS WILL GENERALLY IMPROVE ACROSS THE AREA...BUT OCCASIONAL SHOWERS WILL PERSIST. MVFR CEILINGS WILL LIKELY PERSIST ALONG AND EAST OF A KHVR-KLWT LINE. AFTER 00Z...CLOUDS WILL GENERALLY DECREASE WEST OF THE KHVR-KLWT LINE WITH PATCHY FOG DEVELOPMENT AFTER 06Z...BUT SCATTERED SHOWERS WITH OCCASIONAL MVFR CEILINGS WILL LIKELY PERSIST EAST OF THE LINE. COULSTON && .HYDROLOGY... FLOOD WARNINGS CONTINUE FOR FERGUS AND JUDITH BASIN AND CHOUTEAU COUNTIES. IN ADDITION FLOODING HAS BEEN REPORTED IN EASTERN CASCADE COUNTY SO A FLOOD WARNING HAS BEEN ISSUED FOR CASCADE COUNTY AS WELL. THIS WARNING REPLACES THE FLOOD WATCH THERE. FLOOD WATCHES CONTINUE FOR GALLATIN AND MEAGHER AND HILL AND BLAINE COUNTIES. ADDITIONAL RAINFALL TOTALS OF AN INCH OR MORE OVER PORTIONS OF FERGUS AND BLAINE COUNTIES TO LESS THAN A QUARTER OF INCH OVER PORTIONS OF SOUTHWEST MONTANA ARE EXPECTED THROUGH SUNDAY AFTERNOON. A FLOOD WATCH HAS BEEN ISSUED FOR THE GALLATIN RIVER NEAR LOGAN. && .PREV DISCUSSION... /ISSUED 605 AM MDT SAT MAY 21 2011/ SATURDAY THROUGH MONDAY...RAIN WILL PERSIST IN THE SHORT TERM WITH THE EASTERN BORDER OF THE AREA CONTINUING TO SEE THE HIGHEST AMOUNTS OF TOTAL PRECIPITATION. WIDESPREAD SHOWERS WILL HAVE GAPS OF DRIER AIR AROUND THEM YIELDING A MORE CONVECTIVE LOOKING PRECIP OUTLOOK FOR TODAY WITH LINES OF SHOWERS SEPARATED BY AREAS OF FAIRER WEATHER CONDITIONS. THE PRECIPITATION SHOULD SLOWLY DRIFT EASTWARD. WHILE MODELS FORECAST ARE DISAGREEING ON THE EXACT EXIT TIME...MOST OF THE FORECASTED PRECIPITATION SHOULD CEASE BY SUNDAY MORNING. THE CHANCE OF RESIDUAL SHOWERS AND AFTERNOON THUNDERSTORMS WILL KEEP A CHANCE OF PRECIPITATION OVERNIGHT AND LIKELY SHOWERS SUNDAY AND INTO MONDAY. TEMPERATURES WILL START TO REBOUND AS THIS RELATIVELY WARM SYSTEM IS REPLACED WITH AN INDUCED SHORTWAVE RIDGE. THIS RIDGE WILL ALLOW FOR SOME ADDITIONAL CLEARING...HOWEVER THE SOUTHWEST FLOW FORECASTED WITH THIS RIDGE ALSO APPEARS TO TRANSPORT A DECENT AMOUNT OF MOISTURE AND WILL LIKELY INCREASE THE CHANCE OF SHOWERS. BECAUSE OF ALL THE PRECIPITATION AND NEAR NORMAL TEMPERATURES...HYDROLOGY CONCERNS WILL REMAIN HIGH AS THE POTENTIAL FOR SIGNIFICANT SNOW MELT TO COMBINE WITH THE RAINFALL COULD CREATE SERIOUS FLOODING SITUATIONS ACROSS THE AREA. SUK MONDAY NIGHT THROUGH SATURDAY...A LARGE UPPER LEVEL LOW PRESSURE AREA WILL REMAIN OFF THE PACIFIC NORTHWEST COAST THROUGH THE EXTENDED PERIOD. TWO SEPARATE WEATHER SYSTEMS WILL EJECT FROM THE MAIN UPPER LOW AND BRING AT LEAST A CHANCE OF SHOWERS WITH AFTERNOON/EVENING THUNDERSTORMS TO THE TFX CWA. THE FIRST SYSTEM WILL BRING THE BETTER CHANCE FOR SHOWERS OF THE TWO SYSTEMS...WHICH WILL AFFECT THE AREA MONDAY NIGHT THROUGH TUESDAY NIGHT. THE SECOND SYSTEM WILL FOLLOW CLOSE BEHIND THIS FIRST ONE...RESULTING IN A CHANCE OF SHOWERS AND AFTERNOON/EVENING THUNDERSTORMS CONTINUING THROUGH THURSDAY NIGHT. AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL DECREASE THE CHANCE FOR SHOWERS/THUNDERSTORMS SIGNIFICANTLY FOR FRIDAY AND FRIDAY NIGHT. HOWEVER...THE MAIN UPPER LEVEL LOW WILL SLOWLY APPROACH THE PACIFIC NORTHWEST COAST ON SATURDAY...FOR ANOTHER CHANCE FOR SHOWERS AND AFTERNOON/EVENING THUNDERSTORMS. WEAK COLD FRONTS WILL ACCOMPANY THE FIRST TWO SYSTEMS MENTIONED ABOVE...WHICH WILL ONLY BRIEFLY COOL SLIGHTLY ABOVE NORMAL TEMPERATURES TO SLIGHTLY BELOW NORMAL. COULSTON && .PRELIMINARY POINT TEMPS/POPS... GTF 64 46 68 47 / 90 70 60 40 CTB 67 44 67 45 / 50 50 60 50 HLN 66 46 71 49 / 60 60 50 60 BZN 63 41 70 44 / 80 70 40 40 WEY 54 35 56 37 / 80 40 40 40 DLN 64 41 66 43 / 40 40 50 60 HVR 67 49 69 48 / 100 80 80 40 LWT 56 43 63 44 / 100 100 80 50 && .TFX WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH THROUGH SUNDAY MORNING BLAINE...GALLATIN...HILL... MEAGHER. FLOOD WARNINGS THROUGH MONDAY MORNING FOR CASCADE...FERGUS...JUDITH BASIN...AND CHOUTEAU COUNTIES. FLOOD WATCH FOR THE GALLATIN RIVER NEAR LOGAN. && SHORT TERM...BLANK LONG TERM...BLANK AVIATION...BLANK WEATHER.GOV/GREATFALLS
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE GREAT FALLS MT 915 AM MDT SAT MAY 21 2011 MTZ011>013-047-050-051-054-055-221300- HILL-CASCADE-CHOUTEAU-BLAINE-JUDITH BASIN-FERGUS-MEAGHER-GALLATIN- 915 AM MDT SAT MAY 21 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 CASCADE...CHOUTEAU...FERGUS...AND JUDITH BASIN COUNTIES IN CENTRAL MONTANA. A FLOOD WATCH IS IN EFFECT FOR BLAINE AND HILL COUNTIES IN NORTH CENTRAL MONTANA...AND FOR GALLATIN AND MEAGHER COUNTIES IN SOUTHWEST MONTANA. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY THE FLOOD WARNING IS IN EFFECT THROUGH AT LEAST MONDAY MORNING. THE FLOOD WATCH IS IN EFFECT THROUGH AT LEAST SUNDAY MORNING. ANOTHER WET STORM SYSTEM IS EXPECTED TO MOVE INTO THE REGION SUNDAY NIGHT AND COULD CONTINUE THROUGH TUESDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS REQUESTED ALONG ALL CREEKS AND RIVERS IN THE ABOVE MENTIONED COUNTIES. ANY REPORTS OF FLOODING WOULD BE GREATLY APPRECIATED. MTZ008>010-014-015-044>046-048-049-052-053-221300- BEAVERHEAD-NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER- CENTRAL AND SOUTHERN LEWIS AND CLARK-MADISON-TOOLE-LIBERTY- EASTERN PONDERA-SOUTHERN ROCKY MOUNTAIN FRONT-EASTERN TETON- JEFFERSON-BROADWATER- 915 AM MDT SAT MAY 21 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT PERIODS OF RAIN AND HIGH MOUNTAIN SNOW WILL SPREAD ACROSS THE REGION TODAY AND TONIGHT. THE PRECIPITATION COULD CAUSE ADDITIONAL RISES ON CREEKS...STREAMS...AND RIVERS. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY PERIODS OF RAIN WILL CONTINUE THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK...AS ANOTHER WET STORM SYSTEM IS EXPECTED TO MOVE INTO THE REGION. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
549 AM MDT SAT MAY 21 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0547 AM FLOOD 1 SSE BELT 47.37N 110.92W
05/21/2011 CASCADE MT PUBLIC
BELT CREEK HAS RISEN TO APPOXIMATELY 7.5 FEET NEAR
ARMINGTON. WATER IS RUNNING INTO YARDS AND UP TO A
GARAGE.
&&
NJLPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
742 AM MDT SAT MAY 21 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0729 AM FLOOD 10 ESE LEWISTOWN 47.01N 109.23W
05/21/2011 FERGUS MT TRAINED SPOTTER
SPRING CREEK IS FLOODING INTO LOW AREAS. NO STRUCTURES
THREATENED AT THIS TIME. WATER IS APPROACHING ROAD.
&&
NJLPRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE GREAT FALLS MT
832 AM MDT SAT MAY 21 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0729 AM FLOOD 9 WNW LEWISTOWN 47.13N 109.58W
05/21/2011 FERGUS MT TRAINED SPOTTER
SPRING CREEK IS FLOODING INTO LOW AREAS. NO STRUCTURES
THREATENED AT THIS TIME. WATER IS APPROACHING ROAD.
&&
CORRECTED LOCATION
NJLPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
854 AM MDT SAT MAY 21 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0852 AM FLOOD 5 SW WINDHAM 47.04N 110.22W
05/21/2011 JUDITH BASIN MT TRAINED SPOTTER
WILLOW CREEK IS OUT OF ITS BANKS. FLOODING IS MAINLY IN
FIELDS... NO STRUCTURES IN DANGER AT THIS TIME. WATER IS
UP TO WILLOW CREEK ROAD BUT NOT OVER IT. 1.75 INCHES OF
RAINFALL SINCE THURSDAY.
&&
NJLThe national radar mosaic for the moment the first event began.
3 flood. Local standard time, as filed.
Flooding of Belt Creek in the town of Armington with several buildings and homes either threatened or under water. Montana Fish, Wildlife and Parks closed several Fishing Access sites in the Ulm, Craig and Great Falls area along the Smith and Missouri Rivers.
KFBB reports flooding of Belt Creek in the Monarch area and Dry Fork Creek along Hughesville Road. One house about a foot under water. Bridge wiped out. Restaurant parking lot half flooded.
Flooding occurred on the Smith River 13 miles south of Ulm.
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: 370131, 370415, 370423.