A strong westerly flow aloft produced high surface winds over portions of the Northern Rocky Mountain Front. Wind gusts in excess of 70 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 strong westerly flow aloft produced high surface winds over portions of the Northern Rocky Mountain Front. Wind gusts in excess of 70 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 Aug 22, 4:30 PM MST, 2 hours 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 530 PM MDT MON AUG 22 2011 AVIATION SECTION UPDATED .DISCUSSION... TONIGHT THROUGH WEDNESDAY...WEAK INSTABILITY OVER FAR SOUTHWEST MONTANA ALONG WITH A LITTLE MOISTURE SHOULD LEAD TO ISOLATED THUNDERSTORMS OVER FAR SOUTHWEST MONTANA LATER THIS AFTERNOON. THESE THUNDERSTORMS SHOULD CONTINUE INTO THE EARLY EVENING. OTHERWISE AN UPPER RIDGE WILL BE OVER THE AREA THIS EVENING FOR DRY AND MOSTLY CLEAR CONDITIONS. A WEATHER DISTURBANCE ALOFT WILL ZIP ACROSS SOUTH CENTRAL CANADA TUESDAY MORNING TEMPORARILY FLATTENING THE RIDGE. THE COLD FRONT ASSOCIATED WITH THE DISTURBANCE WILL MOVE ACROSS THE AREA LATE TONIGHT AND EARLY TUESDAY MORNING. LITTLE MOISTURE IS ASSOCIATED WITH IT BUT THERE IS A SMALL CHANCE OF SOME SHOWERS OVER THE ROCKY MOUNTAIN FRONT ON TUESDAY. THE MAIN EFFECT FROM THE FRONT WILL BE GUSTY WINDS. WINDS WILL STAY BELOW HIGH WIND CRITERIA OVER MOST OF THE FORECAST AREA. HOWEVER HAVE POSTED A HIGH WIND WARNING FOR THE LOGAN PASS AREA FOR LATE TONIGHT AND TUESDAY MORNING. THE COLD FRONT WILL BRING COOLER TEMPERATURES TUESDAY...MAINLY IN THE NORTH. IN THE WAKE OF THE DISTURBANCE THE UPPER RIDGE WILL BUILD OVER THE PACIFIC NORTHWEST LATER TUESDAY AND MOVE OVER THE FORECAST AREA TUESDAY NIGHT. THE RIDGE WILL CONTINUE INTO WEDNESDAY. ASSOCIATED WITH THE RIDGE EXPECT CLEAR OR NEARLY CLEAR SKIES WITH WARMER TEMPERATURES ON WEDNESDAY. BLANK THURSDAY THROUGH MONDAY...THE MAIN FEATURE THURSDAY WILL BE AN UPPER LEVEL HIGH PRESSURE RIDGE WHICH WILL CONTINUE THE TREND OF A WARM AND DRY AIRMASS. THIS RIDGE WILL REMAIN QUITE CONSTANT THROUGH SATURDAY ALTHOUGH MOISTURE WILL MOVE UNDERNEATH THE RIDGE AND ALLOW AFTERNOON CONVECTION TO DEVELOP. A SHORTWAVE WILL CROSS THE ROCKIES LATE SATURDAY AND THE AIRMASS WILL COOL SLIGHTLY. HOWEVER...THE RIDGE WILL REMAIN THE DOMINANT FEATURE AND WARM TEMPERATURES WILL RECOVER QUICKLY ON MONDAY. TEMPERATURES WILL REMAIN WELL ABOVE NORMALS THROUGH THE PERIOD. ZELZER && .AVIATION... UPDATED 2330Z. HIGH PRESSURE CONTINUES TO CREATE VFR CONDITIONS OVER THE REGION WITH WIDESPREAD CLEAR SKIES TO SCATTERED CLOUDS THIS AFTN. SMALL AREA OF INSTABILITY IS PRODUCING A FEW SHOWERS IN FAR SOUTHWEST MT WHICH MAY GENERATE OUTFLOW WINDS AROUND 25-30 KTS VCNTY KBZN UNTIL 02Z. CURRENT BREEZY TO GUSTY WINDS OVER THE PLAINS/VALLEYS SHOULD DECREASE TOWARD SUNSET. AN UPPER LEVEL TROF MOVING ALONG THE US/CAN BORDER TONIGHT INTO TUES MORNING WILL BRING BROAD AREA OF STRONG WINDS ACROSS CENTRAL AND NORTH CENTRAL MT TOMORROW...WITH GUSTS OF 25 TO 35 KTS AROUND KGTF/KHLN/KHVR AND 35 TO 45 KTS VCNTY KCTB EXPECTED. WARANAUSKAS && .FIRE WEATHER... THE RED FLAG WARNING FOR ALL FIRE WEATHER ZONES WILL CONTINUE INTO TUESDAY EVENING ALTHOUGH WINDS WILL SUBSIDE AND HUMIDITIES RECOVER SOME OVERNIGHT TONIGHT. TUESDAY STILL LOOKS TO BE WINDIER THAN MONDAY WITH SLIGHTLY HIGHER HUMIDITIES. ON WEDNESDAY WITH WARMER TEMPERATURES EXPECT MINIMUM HUMIDITIES TO DROP ONCE AGAIN. HOWEVER WINDS WILL BE LIGHTER. BASED ON WIND FORECASTS IN THE 15 TO 20 MPH RANGE OVER FIRE WEATHER ZONE 112 ON WEDNESDAY THERE COULD BE CRITICAL FIRE WEATHER CONDITIONS. DO WANT TO MENTION THAT DO NOT SEE ANY THUNDERSTORMS FOR ANY OF THE FIRE WEATHER ZONES THROUGH WEDNESDAY. && .PRELIMINARY POINT TEMPS/POPS... GTF 62 88 55 93 / 0 0 0 0 CTB 58 82 51 88 / 10 10 0 10 HLN 58 88 55 91 / 10 0 0 0 BZN 51 90 48 91 / 10 10 0 0 WEY 37 79 35 82 / 20 10 10 0 DLN 52 85 48 87 / 10 0 0 0 HVR 61 89 52 94 / 10 0 0 0 LWT 57 87 52 91 / 10 0 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 9 PM MDT TUESDAY BLAINE...BROADWATER... CASCADE...CENTRAL AND SOUTHERN LEWIS AND CLARK...CHOUTEAU... EASTERN GLACIER...EASTERN PONDERA...EASTERN TETON...GALLATIN... HILL...JEFFERSON...JUDITH BASIN...LIBERTY...MEAGHER...NORTHERN ROCKY MOUNTAIN FRONT...SOUTHERN ROCKY MOUNTAIN FRONT...TOOLE...FERGUS. HIGH WIND WARNING LOGAN PASS IN GLACIER COUNTY FROM MIDNIGHT MDT TO NOON MDT TUESDAY. && SHORT TERM...BLANK LONG TERM...COULSTON AVIATION...JOH WEATHER.GOV/GREATFALLS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 258 PM MDT MON AUG 22 2011 MTZ010>014-044>055-232100- EASTERN GLACIER-HILL-CASCADE-CHOUTEAU- CENTRAL AND SOUTHERN LEWIS AND CLARK-TOOLE-LIBERTY- EASTERN PONDERA-BLAINE-SOUTHERN ROCKY MOUNTAIN FRONT- EASTERN TETON-JUDITH BASIN-FERGUS-JEFFERSON-BROADWATER-MEAGHER- GALLATIN- 258 PM MDT MON AUG 22 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT A RED FLAG WARNING IS IN EFFECT. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY THE RED FLAG WARNING WILL CONTINUE EFFECT UNTIL 9 PM MDT TUESDAY EVENING. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. MTZ008-015-232100- BEAVERHEAD-MADISON- 258 PM MDT MON AUG 22 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. MTZ009-232100- NORTHERN ROCKY MOUNTAIN FRONT- 258 PM MDT MON AUG 22 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT A RED FLAG WARNING IS IN EFFECT. A HIGH WIND WARNING IS IN EFFECT FOR LOGAN PASS BEGINNING AT MIDNIGHT MDT. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY THE RED FLAG WARNING WILL CONTINUE IN EFFECT UNTIL 9 PM MDT TUESDAY EVENING. THE HIGH WIND WARNING WILL CONTINUE FOR LOGAN PASS UNTIL NOON MDT TUESDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
1 high wind. Local standard time, as filed.
A wind gust to 73 mph was reported at St Mary 13WSW (the Logan Pass Visitor Center of Glacier National Park).
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, August 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: 333384.