Subtropical moisture continued to move into Utah, creating scattered showers and thunderstorms across much of the state. However, the strongest storms were located over southern Utah, where flash flooding and strong thunderstorm winds were both observed.
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.
Subtropical moisture continued to move into Utah, creating scattered showers and thunderstorms across much of the state. However, the strongest storms were located over southern Utah, where flash flooding and strong thunderstorm winds were both observed. A lightning fatality also occurred with these storms.
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 Jul 21, 3:16 PM MST, 1 hour 44 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 416 PM MDT SAT JUL 21 2012 .SYNOPSIS...DEEP MOISTURE HAS SPREAD INTO THE AREA AND WILL REMAIN IN PLACE THROUGH EARLY NEXT WEEK. TEMPERATURES WILL REMAIN NEAR SEASONAL NORMS THROUGH THAT TIME. && .DISCUSSION...MID LEVEL WAVE CURRENTLY OVER CENTRAL UTAH WILL CONTINUE TO LIFT NORTH THROUGH THIS EVENING BEFORE EXITING NORTH AND EAST OVERNIGHT. SAID WAVE WILL PROVIDE FOCUS FOR AFTERNOON/EVENING CONVECTION AS IT HAS OVER THE LAST FEW HOURS. LATEST SPC MESOSCALE ANALYSIS INDICATES MODEST INSTABILITY ACROSS THE AREA WITH MUCAPE RANGING BETWEEN 500-1000 J/KG...AND AN AREA OF INCREASING EFFECTIVE BULK SHEAR ACROSS THE NORTHWEST. HAVE SEEN A FEW HEAVY RAINERS TODAY BUT IN GENERAL STORM CELLS HAVE BEEN SHORT LIVED AND OF THE PULSE VARIETY. THIS SAID...REPORTS OF UP TO 1 INCH IN AN HOUR AND ESTIMATES MORE THAN DOUBLING THAT HAVE BEEN REALIZED THIS AFTERNOON. WILL CONTINUE TO CLOSELY MONITOR THREAT OF FLASH FLOODING FOR PRONE AREAS AS THE ATMOSPHERE IS SOMEWHAT PRIMED...BUT THUS FAR STORM CELLS HAVE GENERALLY SKIRTED THESE AREAS. AFOREMENTIONED SHEAR ACROSS THE NORTHWEST PRIMARILY DRIVEN BY ENTRANCE OF UPPER LEVEL JET ALOFT...THIS IN PLACE BETWEEN THE HIGH TO THE EAST AND UPPER LEVEL LOW SPINNING OVER THE PACNW. MAY SEE BETTER ORGANIZATION ACROSS THE NORTHWESTERN DESERTS OVER THE NEXT FEW HOURS WITH ISOLATED SEVERE STORMS A POTENTIAL RESULT. BULK OF STRONGER CELLS HAVE REMAINED TIED TO OR SKIRTING THE TERRAIN. WITH INCREASED CONVECTIVE TURNOVER AND LATE AFTERNOON TRENDS...EXPECTING OUTFLOWS TO BECOME MORE NUMEROUS SPAWNING OR MAINTAINING ACTIVITY INTO THE VALLEYS OF THE WEST/NORTH. HAVE INCREASED POPS THROUGH THIS EVENING TO SCATTERED COVERAGE FROM THE SOUTHERN SALT LAKE VALLEY SOUTH TO FOLLOW THIS THINKING. DEEP MOISTURE IN PLACE WILL REMAIN ENTRENCHED INTO EARLY NEXT WEEK. PWATS NEAR OR SLIGHTLY ABOVE AN INCH COUPLED WITH DIURNAL DESTABILIZATION WILL MAINTAIN SCATTERED SHOWERS AND STORMS...FOCUSED ALONG AND COINCIDENT WITH ANY RETURN FLOW WAVES. TRENDS OF LATE BRING A FEATURE THROUGH ROUGHLY ONCE EVERY 24 HOURS WITH TIMING THE KEY REGARDING BREADTH OF CONVECTION. WILL CONTINUE TO MONITOR ACTIVITY OVER ARIZONA INTO TOMORROW FOR REMNANT MCV/S THAT COULD TRANSLATE NORTH INTO THE STATE OVER THE NEXT 24 HOURS. HIGH PRESSURE WILL BULGE WEST LATE SUNDAY THROUGH MONDAY...WHILST AFOREMENTIONED PACNW TROUGH SHIFTS EAST INTO THE NORTHERN ROCKIES STATES. GUIDANCE SUGGESTS A REMNANT UPPER LEVEL CIRCULATION CURRENTLY OFF THE CALI COAST WILL TRACK THROUGH THE NORTH DRIVING ACTIVITY MONDAY AFTERNOON AND NIGHT THERE...WHILE TERRAIN BASED ACTIVITY WILL BE MAINTAINED ELSEWHERE. UPON PASSAGE MOISTURE LOOKS TO GET PINNED MORE AND MORE TO THE SOUTH AS A DRIER WESTERLY FLOWS SETS UP BRIEFLY MIDWEEK. THE ECMWF CONTINUES TO BE MORE BULLISH REGARDING EXTENT OF MID LEVEL DRYING VS THE LAST FEW GFS RUNS...HAVE TRENDED TOWARDS THE EC AS LARGE SCALE PATTERN EVOLUTION WOULD SUGGEST A DRY SLOT ENTERING THE STATE. FOR NOW HAVE JUST LOWERED POPS TO SLIGHTLY BELOW CLIMO DUE TO UNRESOLVED INCONSISTENCIES. THE HIGH WILL AMPLIFY TO OUR WEST LATE IN THE WEEK ALLOWING YET ANOTHER RESURGENCE OF MOIST SOUTHERLY FLOW. GUIDANCE QUITE LOCK STEP REGARDING THIS WITH THE ONLY SIGNIFICANT DIFFERENCE BEING THE EXTENT OF MIDWEEK DRYING. && .AVIATION...THE SLC TERMINAL WILL LIKELY SEE VFR CONDITIONS THROUGH THE EVENING. HOWEVER...THERE IS A 20 PERCENT CHANCE THAT SHOWERS AND THUNDERSTORMS COULD DIRECTLY IMPACT THE TERMINAL BETWEEN 23Z AND 03Z AND TEMPORARILY RESTRICT VISIBILITY TO MVFR CONDITIONS. IN ADDITION...ANY SHOWERS OR THUNDERSTORMS IN THE VICINITY OF THE SLC TERMINAL COULD RESULT IN PERIODS OF GUSTY AND/OR ERRATIC WINDS TO 30-35 MPH. MOST LIKELY WIND GUST DIRECTION WILL BE FROM THE SOUTH. && .FIRE WEATHER...SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS THE STATE...AND WILL CONTINUE TO DO SO THROUGH THIS EVENING. WITH ABUNDANT MOISTURE...EXPECT HEAVY RAIN TO ACCOMPANY THE MAJORITY OF THESE STORMS. HOWEVER...ACROSS THE NORTHWESTERN PORTION OF THE STATE...WHERE CONDITIONS ARE A BIT DRIER...THERE EXISTS THE POTENTIAL FOR ISOLATED DRY THUNDERSTORMS. TOMORROW WILL BE QUITE SIMILAR TO TODAY...WITH AFTERNOON THUNDERSTORMS DEVELOPING OVER THE HIGHER TERRAIN. THIS PATTERN WILL PERSIST THROUGH EARLY NEXT WEEK AS MOISTURE REMAINS OVER THE STATE. DRIER AIR WILL MOVE INTO THE STATE MIDWEEK NEXT WEEK...BRINGING A DOWNWARD TREND IN COVERAGE AND INTENSITY OF AFTERNOON CONVECTION. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...NONE. WY...NONE. && MERRILL/STRUTHWOLF/HOSENFELD 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 455 AM MDT SAT JUL 21 2012 UTZ001>016-019>021-517-518-WYZ021-221200- 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- 455 AM MDT SAT JUL 21 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN TWO THIRDS OF UTAH AND SOUTHWEST WYOMING. .DAY ONE...TODAY AND TONIGHT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AFFECT THE REGION THROUGH THE EVENING. CLOUD TO GROUND LIGHTNING...LOCALLY GUSTY WINDS...SMALL HAIL...AND LOCALLY HEAVY RAINFALL ARE THE PRIMARY THREATS. A POTENTIAL EXISTS FOR FLASH FLOODING IN SLOT CANYONS...NORMALLY DRY WASHES...AND BURN SCARS IF THUNDERSTORMS DEVELOP OVER PRONE AREAS. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY MOISTURE WILL REMAIN IN PLACE ACROSS MUCH OF THE OUTLOOK AREA SUNDAY THROUGH AT LEAST THE MIDDLE OF NEXT WEEK. SHOWERS AND THUNDERSTORMS ARE EXPECTED EACH DAY WITH THE GREATEST COVERAGE DURING THE AFTERNOONS AND EVENINGS. THE THREAT OF LOCAL HEAVY RAIN FROM THESE STORMS AND ASSOCIATED FLASH FLOODING WILL ALSO PERSIST INTO NEXT WEEK. THE GREATEST THREAT WILL REMAIN ALONG SLOT CANYONS...NORMALLY DRY WASHES AND BURN SCARS. .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) FOR INFORMATION ON POTENTIAL TRAVEL IMPACTS VISIT... HTTP://WWW.UDOTTRAFFIC.UTAH.GOV/ROADWEATHERFORECAST.ASPX
The Cedar City radar (KICX), 31 km away, was scanning. The volume nearest the first event began at 00:00 UTC.
2 flash flood, 1 lightning, 1 thunderstorm wind. Local standard time, as filed.
Flash flooding occurred in multiple small canyons in Zion National Park, including Telephone Canyon.
A 24-year-old male was fishing at Row Lake, on the west side of Boulder Mountain, on the evening of July 21st. When a thunderstorm moved into the area, both the man and his dog took shelter under a tree. Lightning struck the tree, and both the man and the dog were killed.
Flash flooding occurred on the Fort Pearce Wash, with the gauge along the wash indicating that the flow quickly increased to 935 cfs.
The St. George RAWS recorded a maximum wind gust of 62 mph.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Lightning, Garfield | 2012-07-21 | 24 | Male | Under Tree | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2012Every state in 2012This day in weather historyWarnings in Utah, July 2012
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: 403703, 403653, 403702, 403685.