A strong closed low pressure system off the West Coast produced hail and strong thunderstorm winds.
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 MSO wrote it up.
A strong closed low pressure system off the West Coast produced hail and strong thunderstorm winds.
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 Jul 15, 12:49 PM MST, 4 hours 44 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MISSOULA MT 149 PM MDT FRI JUL 15 2011 .DISCUSSION...CONDITIONS FOR THE REMAINDER OF TODAY SHOULD BE FAIRLY TAME COMPARED TO SATURDAYS FORECAST. PLENTY OF SUN AND A MIX OF FAIR WEATHER CLOUDS WILL ACCOMPANY THIS AFTERNOON AND EVENINGS SKIES. THOUGH...THERE IS A SLIGHT CHANCE FOR THUNDERSHOWERS TO DEVELOP OVER THE BUTTE/BLACKFOOT REGION AS WELL AS ACROSS LEMHI COUNTY IN IDAHO THIS AFTERNOON. SHOULD ANY STORMS DEVELOP...THEY WILL BE ISOLATED AT BEST...BUT THIS STORY WILL LIKELY CHANGE BY TOMORROW. AN ELONGATED UPPER LEVEL TROUGH OFF THE PACIFIC COAST WILL GRADUALLY MOVE INLAND OVERNIGHT...WITH THUNDERSTORMS DEVELOPING AHEAD OF THIS TROUGH (OVER THE NORTHERN ROCKIES AND THROUGH EASTERN WASHINGTON). CONDITIONS WILL BEGIN TO DESTABILIZE SATURDAY MORNING WITH CLOUDS INCREASING THROUGHOUT THE DAY. CENTRAL IDAHO COULD SEE THE FIRST ROUND OF THUNDERSTORMS DEVELOPING EARLIER IN THE DAY...INCLUDING THE MID TO LATE MORNING HOURS. THIS AREA OF THUNDERSTORM DEVELOPMENT WILL THEN OCCUR OVER MOST OF WESTERN MONTANA AFTER NOON...WITH STRONGER THUNDERSTORMS OCCURRING BY LATE AFTERNOON. THREATS EXPECTED FROM DEVELOPING STORMS WILL BE BRIEF BUT HEAVY DOWNPOURS...AS WELL AS VERY GUSTY WINDS. THIS WILL POSE A CONCERN FOR THOSE WHO ARE PLANNING ON BOATING ON FLATHEAD LAKE...AS WELL AS OTHER AREA LAKES. WITH FLATHEAD LAKE BEING JUST A FEW INCHES BELOW FULL POOL...GUSTY WINDS THAT ACCOMPANY THUNDERSTORMS MOVING OVER THE LAKE COULD MAKE FOR DIFFICULT BOATING CONDITIONS. THUNDERSTORMS COULD LAST INTO THE LATE EVENING...DYING OFF BY MIDNIGHT OR SHORTLY AFTER...DEPENDING ON THE INTENSITY AND LASTING NATURE OF THE STORMS THEMSELVES. A FEW LINGERING RAIN SHOWERS IN NORTHWEST MONTANA WILL OCCUR THROUGH SUNDAY MORNING...BUT SHOULD DRY UP COMPLETELY BY SUNDAY AFTERNOON. CONDITIONS WILL THEN REMAIN QUITE PLEASANT DURING THROUGH SUNDAY NIGHT. MONDAY THROUGH FRIDAY...STARTING OUT WITH THE HOTTEST DAY OF THE YEAR ON MONDAY AS MASSIVE CENTRAL US HIGH PRESSURE BUILDS WEST. TUESDAY WILL BE VERY WARM AGAIN AHEAD OF AN APPROACHING PACIFIC COLD FRONT WHICH WILL BRING BREEZY CONDITIONS LATE IN THE DAY AND AN INCREASING CHANCE OF PRECIPITATION. THEN COOLER THAN NORMAL CONDITIONS ARE EXPECTED FOR THE REMAINDER OF THE WEEK WITH SOME STRAY SHOWERS AND THUNDERSTORMS. && .AVIATION...FAIR FLYING CONDITIONS EXPECTED FOR THE REST OF TODAY...THOUGH SOME CUMULONIMBUS DEVELOPMENT WITH AN ISOLATED THUNDERSHOWER IS POSSIBLE OVER KBTM AND KSMN THIS AFTERNOON AND EVENING. THE TIME FRAME OF GREATER CONCERN WILL BE SATURDAY...AS STRONG THUNDERSTORMS ARE POSSIBLE DURING THE DAY AND THROUGH SATURDAY NIGHT. SOME STORMS MAY BEGIN EARLY SATURDAY MORNING ACROSS CENTRAL IDAHO...WITH MOST LOCATIONS AND TERMINALS EXPERIENCING LIGHTNING...BRIEF HEAVY DOWNPOURS...AND GUSTY WINDS FROM STORMS THROUGHOUT THE DAY TOMORROW. && NOTE: FLOOD WATCHES...WARNINGS AND ADVISORIES WILL NOT BE LISTED BELOW. .MSO WATCHES/WARNINGS/ADVISORIES... MT...NONE. ID...NONE. && SHORT TERM...ALLEGRETTO LONG TERM....SIGLER AVIATION...ALLEGRETTO
The Missoula radar (KMSX), 189 km away, was scanning. The volume nearest the first event began at 00:34 UTC.
1 thunderstorm wind, 1 heavy rain. Local standard time, as filed.
Kriley Creek RAWS measured a gust of 73 mph. This site is at 5200 feet elevation.
A police officer estimated 1.50 inches of rain in 30 minutes.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2011Every state in 2011This day in weather historyWarnings in Idaho, July 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: 331108, 331107.