Showers and thunderstorms continued to form in a moist airmass across the state of Utah in the first few days of August. The strongest of these storms produced primarily severe wind gusts and hail in northern Utah, while producing heavy rain and flash flooding in southern and eastern Utah.
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 SLC wrote it up.
Showers and thunderstorms continued to form in a moist airmass across the state of Utah in the first few days of August. The strongest of these storms produced primarily severe wind gusts and hail in northern Utah, while producing heavy rain and flash flooding in southern and eastern Utah.
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 Salt Lake City, UT wrote its last area forecast discussion before the first event at Aug 1, 8:55 AM MST, 5 hours 5 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 955 AM MDT MON AUG 1 2011 .SYNOPSIS...A VERY MOIST AIR MASS IN PLACE ACROSS THE GREAT BASIN WILL SLOWLY DRY FROM THE WEST THROUGH MIDWEEK. && .DISCUSSION...SHORTWAVE TROUGH WHICH BROUGHT FAIRLY WIDESPREAD PRECIPITATION TO MUCH OF NORTHERN UTAH EARLY THIS MORNING CONTINUES TO LIFT NORTHEAST AWAY FROM THE AREA. AS A RESULT PRECIPITATION HAS DIMINISHED IN COVERAGE...AND PLAN TO UPDATE FORECAST TO REFLECT THIS TREND. IN THE WAKE OF THIS WAVE...A VERY MOIST AIRMASS REMAINS IN PLACE ACROSS THE REGION...WITH SURFACE DEW POINTS IN THE 60S...AND PW VALUES WELL OVER AN INCH. DESPITE SUBSIDENCE ASSOCIATED WITH SHORTWAVE RIDGING BUILDING INTO THE REGION TODAY...THIS MOISTURE SHOULD BE SUFFICIENT TO ALLOW FOR ADDITIONAL SHOWERS AND THUNDERSTORMS THIS AFTERNOON...PARTICULARLY ALONG LINGERING SURFACE TROUGH ACROSS CENTRAL UT. DEEP LAYER SOUTHWESTERLY FLOW LOOKS TO DEVELOP ACROSS THE REGION THROUGHOUT THE WEEK ALLOWING FOR A GENERAL DRYING TREND. DESPITE LOSS OF DEEPER TROPICAL MOISTURE...SUFFICIENT MID LEVEL MOISTURE LOOKS TO REMAIN OVER THE REGION...ALLOWING FOR A THREAT OF SHOWERS AND THUNDERSTORMS EACH AFTERNOON/EVENING. && .AVIATION...SHOWERS WITH CIGS IN THE 4-5 KFT RANGE MAY LINGER AS LATE AS 18Z BEFORE SCATTERING OUT. OTHERWISE WINDS LOOK TO REMAIN PREDOMINANTLY NORTHWESTERLY THROUGHOUT THE DAY...ALTHOUGH ERRATIC WINDS CAN BE EXPECTED WITH SHOWERS THROUGH 18Z. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...NONE. WY...NONE. && SEAMAN FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE) FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION VISIT... HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SALT LAKE CITY UT 534 AM MDT MON AUG 1 2011 UTZ001>016-019>021-517-518-WYZ021-021200- CACHE VALLEY/UTAH PORTION-NORTHERN WASATCH FRONT- SALT LAKE AND TOOELE VALLEYS-SOUTHERN WASATCH FRONT- GREAT SALT LAKE DESERT AND MOUNTAINS-WASATCH MOUNTAIN VALLEYS- WASATCH MOUNTAINS I-80 NORTH-WASATCH MOUNTAINS SOUTH OF I-80- WESTERN UINTA MOUNTAINS-WASATCH PLATEAU/BOOK CLIFFS- WESTERN UINTA BASIN-CASTLE COUNTRY-SAN RAFAEL SWELL- SANPETE/SEVIER VALLEYS-WEST CENTRAL UTAH-SOUTHWEST UTAH- UTAHS DIXIE AND ZION NATIONAL PARK-SOUTH CENTRAL UTAH- GLEN CANYON RECREATION AREA/LAKE POWELL-CENTRAL MOUNTAINS- SOUTHERN MOUNTAINS-SOUTHWEST WYOMING- 534 AM MDT MON AUG 1 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN TWO THIRDS OF UTAH AND FAR SOUTHWEST WYOMING. .DAY ONE...TODAY AND TONIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL PERSIST ACROSS THE NORTHERN OUTLOOK AREA THROUGH THE MORNING HOURS...MOST NUMEROUS NORTH OF ABOUT SALT LAKE CITY. SOME OF THE SHOWERS WILL PRODUCE LOCALLY HEAVY RAINS WITH A POTENTIAL OF MINOR STREET FLOODING IN URBAN AREAS ALONG THE NORTHERN WASATCH FRONT. SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS MOST OF THE OUTLOOK AREA THIS AFTERNOON AND CONTINUE INTO THE EVENING... WITH A CONTINUED POTENTIAL OF ISOLATED HEAVY RAINS. MOST OF THE SHOWERS SHOULD DISSIPATE AFTER MIDNIGHT TONIGHT. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY A GRADUAL DRYING TREND WILL BEGIN TUESDAY AND CONTINUE THROUGH THE END OF THE WEEK. ENOUGH MOISTURE WILL REMAIN IN PLACE TUESDAY AND WEDNESDAY HOWEVER FOR SCATTERED SHOWERS AND THUNDERSTORMS EACH AFTERNOON AND EVENING. STORMS WILL BE A LITTLE LESS NUMEROUS THURSDAY...AND ONLY ISOLATED COVERAGE IS EXPECTED OVER THE NORTHEASTERN MOUNTAINS FRIDAY. IT APPEARS AT THIS TIME THAT THE WEEKEND SHOULD BE DRY FOR MOST OF THE OUTLOOK AREA WITH ONLY A SMALL THREAT OF THUNDERSTORMS ACROSS THE FAR SOUTH. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)
The Cedar City radar (KICX), 172 km away, was scanning. The volume nearest the first event began at 20:59 UTC.
5 flash flood, 4 thunderstorm wind, 4 hail. Local standard time, as filed.
Flash flooding was reported along Pleasant Creek, Sandy Creek, and Burro Wash in and near Capitol Reef National Park.
The Causeway sensor in the Dugway Proving Ground mesonet recorded a maximum wind gust of 62 mph.
Two sensors in the Dugway Proving Ground mesonet recorded strong wind gusts with a thunderstorm moving through the area. The Juliet Road sensor recorded a maximum gust of 59 mph, while the North Salt Flats sensor recorded a 58 mph wind gust.
The Interstate 80 sensor recorded a maximum wind gust of 58 mph.
The University of Utah WBB sensor recorded a maximum wind gust of 63 mph.
Heavy rain caused flash flooding along Wahweep Canyon near Big Water.
Park rangers at Capitol Reef National Park reported a large flash flood along Sulpher Creek.
Flash flooding occurred along Clear Creek Canyon Road near Fremont Indian State Park. This flooding was exacerbated by the rain falling on an old burn scar, which allowed debris to flow over the road.
Hail with a diameter of 0.75 inches was reported near Payson.
Large hail was observed on the west side of the Salt Lake Valley, with 1.5 inch diameter hail reported near Kearns and 1 inch hail reported in West Valley City.
Hail with a diameter of 0.75 inches was observed near Circleville. This thunderstorm also produced very heavy rain over the area.
A participant of the Cooperative Observer Program, near Alpine, reported hail with a diameter of 0.75 inches.
Flash flooding occurred near the town of Angle due to heavy rainfall.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2011Every state in 2011This day in weather historyWarnings in Utah, 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: 344940, 345076, 345075, 345077, 345078, 344968, 344942, 344980, 345072, 345071, 345073, 345074, 344986.