Monsoon moisture returned to Utah on August 17, helping to produce heavy thunderstorms across the state, which resulted in several flash floods.
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.
Monsoon moisture returned to Utah on August 17, helping to produce heavy thunderstorms across the state, which resulted in several flash floods.
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 17, 8:35 AM MST, 1 hour 5 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 935 AM MDT SAT AUG 17 2013 .SYNOPSIS...WITH SOUTHERLY FLOW IN PLACE...A MOIST AIRMASS WILL MOVE NORTHWARD INTO THE STATE TODAY. HIGH PRESSURE WILL FLATTEN TOMORROW CAUSING SOME DRYING BEFORE MOISTURE RETURNS IN EARNEST BEGINNING MONDAY. DRIER AIR WILL MOVE INTO WESTERN UTAH BEGINNING WEDNESDAY. && .DISCUSSION...HIGH PRESSURE REMAINS CENTERED EAST OF THE FORECAST AREA THIS MORNING...ALLOWING A WEST TO SOUTHWEST FLOW TO DRAW MOISTURE NORTHWARD. PLENTY OF ACTIVITY HAS ALREADY COMMENCED ACROSS SOUTHERN UTAH FROM THE MOUNTAINS EASTWARD AND HAVE UPDATED MORNING FORECAST TO ADDRESS THIS. GOES SATELLITE DERIVED PW IS IN THE 1.0 TO 1.2 INCH RANGE ACROSS SOUTHEAST UTAH AND PORTIONS OF THE CENTRAL MOUNTAINS...WITH VALUES IN THE 0.6 TO 0.8 INCH RANGE ELSEWHERE. DRY LIGHTNING A POSSIBILITY WITH ANY CONVECTION THAT DEVELOPS ACROSS NORTHWEST UTAH AS THE BOUNDARY LAYER REMAINS RELATIVELY DRY. ELSEWHERE ACROSS THE WARNING AREA...INCREASED MOISTURE...GOOD INSTABILITY...AND LIGHT FLOW WILL ENHANCE THE POSSIBILITY OF HEAVY RAIN WITH STORMS. STILL THINK THE THREAT OF FLASH FLOODING IS SMALL AT THIS TIME...ALTHOUGH WILL HAVE TO KEEP AN EYE ON BURN SCARS...AND SLOT CANYONS WEST OF LAKE POWELL. && .AVIATION...SCATTERED CUMULUS CLOUDS BUILDING AROUND 8-9 KFT LATE THIS MORNING MAY BRIEFLY TURN TO CEILINGS WITH A SMALL CHANCE OF PRECIPITATION AFTER 20Z. THUNDERSTORMS FORMING ON THE SURROUNDING HIGH TERRAIN MAY PRODUCE ERRATIC OUTFLOW WINDS AT THE TERMINAL BETWEEN 21Z TO 03Z. PREVAILING SURFACE WINDS SHOULD REMAIN BASICALLY SOUTHERLY THROUGH 18-20Z...THEN TURN TO LIGHT NORTHWEST THROUGH 01-02Z. && .FIRE WEATHER...EXTREME FIRE BEHAVIOR IS EXPECTED ACROSS NORTHWEST UTAH AGAIN TODAY AS TEMPERATURES REMAIN ON THE HOT SIDE AND RH VALUES HAVE YET TO RESPOND TO THE ADVANCING MOISTURE PLUME COMING UP FROM THE SOUTH. SUFFICIENT MID-LEVEL MOISTURE HAS MOVED INTO NORTHERN UTAH FOR HIGH-BASED CONVECTION THIS AFTERNOON AND EVENING. RAINFALL WILL BE MINIMAL WITH THIS CONVECTION...SO WINDS AND LIGHTNING WILL BE THE MAIN THREAT TODAY. HAVE ISSUED A RED FLAG WARNING FOR ZONE 478 FOR THIS AFTERNOON THROUGH MID-EVENING. DOWN SOUTH SCATTERED CONVECTION IS EXPECTED WITH A BETTER THREAT FOR WETTING RAIN ACROSS THE HIGHER TERRAIN OF SOUTHERN AND CENTRAL UTAH THIS AFTERNOON AND BEYONDS. MOISTURE WILL CONTINUE TO DEEPEN ACROSS THE DISTRICT LATE IN THE WEEKEND AND THROUGH AT LEAST THE FIRST HALF OF THE UPCOMING WEEK. WETTING RAINS...HIGHER RH VALUES AND MODESTLY COOLER TEMPERATURES WILL BECOME MORE COMMON THROUGH MIDWEEK OWING TO THE DEEP LAYER MOISTURE ACROSS THE STATE. DRIER AIR WILL WORK INTO THE FAR WESTERN DISTRICTS LATE IN THE WEEK...WITH SUFFICIENT MOISTURE ACROSS THE SOUTHERN AND EASTERN DISTRICT TO MAINTAIN CONVECTION INTO THE END OF THE WEEK. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR UTZ478. WY...NONE. && PUBLIC/AVIATION...YOUNG FIRE WEATHER......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 426 AM MDT SAT AUG 17 2013 UTZ001>016-019>021-517-518-WYZ021-181030- 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- 426 AM MDT SAT AUG 17 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN TWO THIRDS OF UTAH AND SOUTHWEST WYOMING. .DAY ONE...TODAY AND TONIGHT MOISTURE OVER SOUTHERN UTAH WILL SPREAD NORTHWARD TODAY...ALLOWING SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP OVER MUCH OF THE FORECAST AREA THROUGH THIS EVENING. BRIEF HEAVY RAIN IS POSSIBLE WITH THE STORMS OVER SOUTHERN UTAH...WHICH COULD PRODUCE ISOLATED FLASH FLOODING. THE THREAT IS GREATEST IN SLOT CANYONS AND NORMALLY DRY WASHES. OVER NORTHERN UTAH...ANY STORMS THAT DEVELOP MAY HAVE GUSTY OUTFLOW WINDS ASSOCIATED WITH THEM. ADDITIONALLY...DRY LIGHTNING IS POSSIBLE WITH THESE STORMS AND THIS COULD LEAD TO NEW WILDFIRE STARTS. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY THE AIRMASS OVER THE OUTLOOK AREA WILL DRY OUT A BIT ON SUNDAY...BUT MOISTURE IS EXPECTED TO INCREASE IN EARNEST MONDAY AND TUESDAY. HEAVY RAIN WILL BECOME THE MAIN THREAT WITH SHOWERS AND THUNDERSTORMS...PARTICULARLY OVER CENTRAL AND SOUTHERN UTAH...DURING THIS TIME. DRIER AIR WILL MOVE INTO WESTERN UTAH WEDNESDAY THROUGH FRIDAY. MOISTURE WILL REMAIN OVER EASTERN UTAH DURING THIS TIME...KEEPING THE THREAT OF THUNDERSTORMS IN THE FORECAST. .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), 163 km away, was scanning. The volume nearest the first event began at 16:39 UTC.
5 flash flood, 1 debris flow. Local standard time, as filed.
Widespread flash flooding was reported along many normally dry washes and canyons, including Spooky Gulch, 25 Mile Wash, the Egypt 3 slot canyon, and several others.
Heavy rain caused a flash flood on Huntington Creek and a debris flow off of the Seeley Fire burn scar. Flooding impacted the Huntington Power Plant, with water having to be diverted around the plant. Logs, mud, and rocks were in the river as it passed the power plant.
A debris flow occurred off of the Clay Springs Fire burn scar, with debris flowing out of the southwest aspect of the scar. Flood waters were as tall as four feet high as it ran toward US Route 50, but ran alongside the road rather than cross over it.
Heavy rain caused a debris flow off the Seeley Fire burn scar, covering parts of State Route 32 with mud.
Flash flooding was reported along the Upper Escalante drainage near State Route 12.
Flash flooding was reported in the Johnson Canyon area, as well as Lick Wash. In Lick Wash, hikers scrambled out of the wash for an hour and a half to get away from the flood waters.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2013Every state in 2013This day in weather historyWarnings in Utah, August 2013
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: 474814, 474831, 474833, 474830, 474817, 474823.