A mid level circulation over southwest Montana brought widespread heavy rainfall. This same area received significant rainfall the week before.
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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 MSO wrote it up.
A mid level circulation over southwest Montana brought widespread heavy rainfall. This same area received significant rainfall the week before. This rainfall in addition to a heavy snow pack had saturated the ground with streams and rivers running high.
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 Missoula, MT wrote its last area forecast discussion before the first event at Jun 7, 8:01 AM MST, 4 hours 59 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MISSOULA MT 901 AM MDT TUE JUN 7 2011 .UPDATE...ADJUSTED CHANCES OF PRECIPITATION ACROSS NORTH CENTRAL IDAHO AND WESTERN MONTANA TODAY. && .DISCUSSION...UPPER LOW CURRENTLY EAST OF THE DIVIDE IS SPILLING PRECIPITATION ACROSS WESTERN MONTANA THIS MORNING. THE MID LEVEL CIRCULATION IS FURTHER SOUTH THAN PREVIOUSLY FORECAST SO THE HEAVIER STRATIFORM PRECIPITATION IS CONFINED ALONG THE DIVIDE AND SOUTHWEST MONTANA. FURTHER TO THE WEST...A MORE SHOWERY REGIME EXISTS...SO PRECIPITATION AMOUNTS WILL BE LESS. THERE IS AN UPPER LEVEL WAVE ON THE BACK SIDE OF THE UPPER LOW KEEPING A STEADY BAND OF RAIN FROM HAPPYS IN THROUGH PLANS AND LOLO PASS TO POINTS EAST. THIS BAND WILL MOVE THROUGH BY MID MORNING BUT INSTABILITY WILL KEEP SHOWERS IN THE FORECAST THROUGH THIS AFTERNOON. WITH DECREASED PRECIPITATION OVER NORTH CENTRAL IDAHO AND NORTH WEST MONTANA...TEMPERATURES MAY BE A BIT WARMER THAN PREVIOUSLY FORECAST. HAVE ADJUSTED TEMPERATURES IN THESE AREAS UP A FEW DEGREES AS A RESULT. && .AVIATION...WIDESPREAD PERSISTENT RAIN WILL AFFECT THE NORTHERN ROCKIES THE NEXT 24 HOURS. EXPECT LOW CLOUD DECKS AND MOUNTAIN OBSCURATIONS. VISIBILITIES MAY BE REDUCED IN AREAS OF HEAVIER SHOWERS. RAINFALL MAY EASE A BIT BY NIGHTFALL TONIGHT...HOWEVER LOW CLOUD DECKS AND SHALLOW FOG MAY ACCOMPANY THE OVERNIGHT HOURS DESPITE LIGHTER RAINFALL. && .PREV DISCUSSION... /ISSUED 854 AM MDT TUE JUN 7 2011/ ..SIGNIFICANT RAINFALL WILL ACCELERATE SNOWMELT AND MANY MAINSTEM RIVER AND SMALL STREAM RISES TODAY THROUGH THURSDAY... DISCUSSION...CLOSED LOW SPINNING OVER THE REGION IS PRODUCING WIDESPREAD RAINFALL. THE FOCUS OF THE MOST PERSISTENT AND AMOUNTS OF RAIN IS OCCURRING ALONG THE CONTINENTAL DIVIDE THROUGH SOUTHWEST AND WEST CENTRAL MONTANA INTO CENTRAL IDAHO. PERSISTENT RAIN WILL CONTINUE IN THESE AREAS THROUGH THE MORNING HOURS AND DECREASE TO MORE OF A SHOWERY REGIME BY THIS EVENING AS THE UPPER LOW MOVES EASTWARD INTO CENTRAL MONTANA. RIGHT BEHIND THIS EXITING LOW IS ANOTHER UPPER LEVEL CLOSED LOW THAT WILL ENTER NORTHWEST MONTANA THIS EVENING AND IMPACT THE ENTIRE NORTHERN ROCKIES AGAIN WITH PERSISTENT SIGNIFICANT RAINS THROUGH MUCH OF THE DAY WEDNESDAY. THIS UPPER LOW WILL EXIT THE REGION WEDNESDAY NIGHT. THE COMBINATION OF SIGNIFICANT RAINFALL ACCUMULATIONS OVER SNOW AND WARM TEMPERATURES AT THESE HIGHER ELEVATIONS WILL HELP TO ACCELERATE SNOWMELT AND INCREASE RISES ON RIVERS AND SMALL STREAMS ACROSS THE ENTIRE REGION. FLOOD WATCHES HAVE BEEN POSTED AS SEVERAL RIVERS HAVE THE POTENTIAL TO APPROACH OR EXCEED FLOOD STAGE OVER THE NEXT 24 TO 48 HOURS. THURSDAY THROUGH SUNDAY...AN ACTIVE WEATHER PATTERN WILL CONTINUE AS A SERIES OF SHORTWAVE TROUGHS MOVES THROUGH THE WESTERLY FLOW THAT WILL CONTINUE OVER THE NORTHWESTERN UNITED STATES. A FEW BREAKS IN THE ACTION CAN BE EXPECTED BUT FOR THE MOST PART THE WEATHER WILL STAY UNSETTLED THROUGH THE WEEKEND. WARMER AIR MOVING INTO THE REGION WILL ALLOW A SLIGHT WARMING TREND BUT NOTHING AS WARM AS THE PAST FEW DAYS IN THE NEAR FUTURE. AVIATION...WIDESPREAD PERSISTENT RAIN WILL AFFECT THE NORTHERN ROCKIES THE NEXT 24 HOURS. EXPECT LOW CLOUD DECKS AND MOUNTAIN OBSCURATIONS. VISIBILITIES MAY BE REDUCED IN AREAS OF HEAVIER SHOWERS. RAINFALL MAY EASE A BIT BY NIGHTFALL TONIGHT...HOWEVER LOW CLOUD DECKS AND SHALLOW FOG MAY ACCOMPANY THE OVERNIGHT HOURS DESPITE LIGHTER RAINFALL. NOTE: FLOOD WATCHES...WARNINGS AND ADVISORIES WILL NOT BE LISTED BELOW. && NOTE: FLOOD WATCHES...WARNINGS AND ADVISORIES WILL NOT BE LISTED BELOW. .MSO WATCHES/WARNINGS/ADVISORIES... MT...NONE. ID...NONE. && UPDATE...MEAD PREVIOUS DISCUSSION....RPN/LOEFFELBEIN AVIATION...ALLEGRETTO
The national radar mosaic for the moment the first event began.
2 flood. Local standard time, as filed.
Cottonwood creek flooded parts of the town of Deer Lodge and down stream.
Boulder creek near Maxville flooded and isolated one resident. A road flooded near the east fork of Rock creek. Debris piled up against many bridges across the county. Many residents protected their property with sandbags.
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, June 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: 314904, 314624.