Several severe thunderstorms formed in Utah in the middle of August, primarily across the northern half of the state. Most of these storms produced strong gusty winds, while a couple produced severe hail.
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.
Several severe thunderstorms formed in Utah in the middle of August, primarily across the northern half of the state. Most of these storms produced strong gusty winds, while a couple produced severe hail.
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 13, 2:47 PM MST, 3 hours 13 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 347 PM MDT SAT AUG 13 2011 .SYNOPSIS...MOISTURE WILL SPREAD NORTHWARD INTO THROUGH TONIGHT. A DRIER AIRMASS WILL MOVE IN BEGINNING TOMORROW AFTERNOON...REMAINING IN PLACE FOR MUCH OF THE WEEK. && .DISCUSSION...SOUTHERLY FLOW HAS DEVELOPED OVER THE FORECAST AREA THIS AFTERNOON ON THE BACKSIDE OF THE HIGH PRESSURE RIDGE. THIS IS ALLOWING MONSOONAL MOISTURE TO MAKE ITS WAY INTO THE AREA FROM THE SOUTH. PW VALUES OF UP TO 0.7 INCHES ARE BEING OBSERVED AS FAR NORTH AS CENTRAL UTAH. SHOWERS AND THUNDERSTORMS ARE BEGINNING TO DEVELOP THIS AFTERNOON...PRIMARILY OVER SOUTHERN UTAH. MOST OF THE INCREASE IN MOISTURE HAS BEEN OBSERVED AT MID AND UPPER LEVELS...HOWEVER...LEAVING THE LOWER LEVELS DRY. AS A RESULT...GUSTY WINDS WILL BE THE PRIMARY THREAT WITH SHOWERS AND THUNDERSTORMS THROUGH THIS EVENING. GUIDANCE INDICATES THAT THIS RETURN OF MONSOONAL MOISTURE WILL BE SHORT LIVED...AS A PACIFIC NORTHWEST TROUGH IS PROGGED TO MOVE ONSHORE TOMORROW...RESULTING IN A MORE WESTERLY FLOW OVER THE FORECAST AREA BY TOMORROW AFTERNOON. THIS WILL ALLOW DRIER AIR TO MOVE IN FROM THE WEST...MAKING ITS WAY INTO NORTHERN UTAH AS EARLY AS TOMORROW AFTERNOON. A THREAT FOR HEAVY RAIN WILL REMAIN OVER SOUTHEAST UTAH...WHERE PWS WILL REMAIN IN EXCESS OF ONE INCH. HOWEVER...BEST DYNAMICS FOR CONVECTION WILL BE CLOSER TO THE JET OVER NORTHERN UTAH. BECAUSE OF THIS...HAVE KEPT AT LEAST SCATTERED WORDING OVER THE ENTIRE FORECAST AREA TOMORROW AFTERNOON AND EVENING. DRIER AIR IS EXPECTED TO MOVE OVER THE FORECAST AREA IN EARNEST ON MONDAY...REMAINING IN PLACE THROUGH WEDNESDAY AS THE PREVIOUSLY MENTIONED TROUGH SKIRTS ACROSS THE CANADIAN BORDER. TOWARD THE END OF THE WORK WEEK...MODELS INDICATE THAT THE RIDGE WILL FLATTEN...ALLOWING MONSOONAL MOISTURE TO WORK ITS WAY BACK IN. HOWEVER...MODELS HAVE BEEN INCONSISTENT ON THE TIMING OF THIS MOISTURE RETURN. && .AVIATION...SURFACE WINDS AT THE SLC TERMINAL ARE EXPECTED TO SWITCH TO THE NORTHWEST BETWEEN 22Z AND 00Z...WITH A SLIGHT CHANCE THAT WINDS REMAIN SOUTHERLY THROUGH THE REST OF THE DAY. THERE IS A 20 PERCENT CHANCE THAT SHOWERS OR THUNDERSTORMS WILL IMPACT THE TERMINAL BETWEEN 02Z AND 10Z...WITH GUSTY ERRATIC WINDS BEING THE MOST LIKELY IMPACT. && .FIRE WEATHER...SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER SOUTHWESTERN UTAH AS MOISTURE MAKES ITS WAY INTO THE STATE. MOISTURE WILL CONTINUE TO MOVE NORTHWARD OVERNIGHT...ALLOWING CONVECTION TO DEVELOP OVER CENTRAL AND NORTHERN UTAH THIS EVENING. LIGHTNING IS THE MAIN CONCERN WITH THESE STORMS...AS FUELS ARE CRITICALLY DRY ACROSS PORTIONS OF THE STATE. MOISTURE WILL GET PUSHED EASTWARD TOMORROW. HOWEVER...ENOUGH MOISTURE WILL REMAIN THAT CONVECTION IS EXPECTED TO DEVELOP OVER THE HIGHER TERRAIN. AGAIN...LIGHTNING WILL BE THE BIGGEST THREAT ASSOCIATED WITH THESE STORMS. WINDS IN THE VICINITY OF THUNDERSTORMS WILL BE GUSTY AND ERRATIC. SOUTHWEST WINDS WILL PICK UP MONDAY AFTERNOON. THERE IS THE POTENTIAL FOR HAZARDOUS FIRE WEATHER CONDITIONS TO DEVELOP MONDAY. HOWEVER...ENOUGH UNCERTAINTY EXISTS CONCERNING HOW QUICKLY MOISTURE IN THE AREA LINGERS...AND SO DID NOT ISSUE A FIRE WEATHER WATCH. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...NONE. WY...NONE. && PUBLIC...TRAPHAGAN FIRE WEATHER...HOSENFELD AVIATION...SCHOENING 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 247 AM MDT SAT AUG 13 2011 UTZ001>016-019>021-517-518-WYZ021-141300- 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- 247 AM MDT SAT AUG 13 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN TWO THIRDS OF UTAH AND SOUTHWEST WYOMING. .DAY ONE...TODAY AND TONIGHT MOISTURE WILL SURGE INTO UTAH FROM ARIZONA STARTING TODAY. ON THE LEADING EDGE...DRY THUNDERSTORMS WITH LIGHTNING AND STRONG OUTFLOW WINDS WILL BE POSSIBLE ACROSS MAINLY SOUTHERN UTAH THROUGH TONIGHT. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY AS THE MOISTURE CONTINUES TO SURGE NORTHWARD...DRY THUNDERSTORMS WITH LIGHTNING AND STRONG OUTFLOW WINDS WILL BE POSSIBLE ACROSS MAINLY NORTHERN UTAH SUNDAY. SOUTH OF INTERSTATE 80...ENOUGH MOISTURE WILL BE IN PLACE FOR THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. AS THUNDERSTORM ACTIVITY INCREASES SUNDAY AFTERNOON AND EVENING...LARGE HAIL AND LOCALLY DAMAGING WINDS WILL BECOME POSSIBLE. DRIER CONDITIONS ARE FORECAST HEADING INTO MID WEEK. WHEN COMBINED WITH AN INCREASE IN WINDS...CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE WHERE FUELS HAVE CURED ACROSS FAR WEST CENTRAL AND SOUTHWEST UTAH MONDAY. THE THREAT OF ISOLATED THUNDERSTORMS WILL RETURN MAINLY TO THE HIGHER TERRAIN FRIDAY. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. ROGOWSKI FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)
The Salt Lake City radar (KMTX), 209 km away, was scanning. The volume nearest the first event began at 00:59 UTC.
6 thunderstorm wind, 2 hail. Local standard time, as filed.
The I-15 Northbound at the Sevier River UDOT sensor recorded a maximum wind gust of 66 mph.
The Interstate 80 sensor in the Dugway Proving Ground mesonet recorded a maximum wind gust of 58 mph.
The Playa Station sensor in the Dugway Proving Ground mesonet recorded a maximum wind gust of 68 mph.
The North Salt Flats sensor in the Dugway Proving Ground mesonet recorded a wind gust of 58 mph.
The wind sensor at Antelope Island State Park recorded a maximum wind gust of 70 mph.
The Syracuse sensor in the air quality mesonet recorded a wind gust of 65 mph.
Hail with a diameter of 0.75 inches was reported along the Scenic Drive in Capitol Reef National Park.
The Emery County Dispatch reported hail with a diameter of 1 inch in Huntington.
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: 345081, 345082, 345084, 345085, 345083, 345086, 345079, 345080.