Showers and thunderstorms developed across the southern half of Utah on August 22, and flash flooding was reported at Capitol Reef National Park.
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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 developed across the southern half of Utah on August 22, and flash flooding was reported at Capitol Reef National Park.
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 22, 1:59 PM MST, 1 hour 16 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 259 PM MDT SAT AUG 22 2015 .SYNOPSIS...WEAK COLD FRONT OVER SOUTHERN UTAH WILL ERODE THIS EVENING. A RIDGE OF HIGH PRESSURE WILL BUILD OVER THE REGION ON SUNDAY...THEN PERSIST INTO EARLY NEXT WEEK. MOISTURE WILL SPREAD NORTHWARD ACROSS THE AREA MIDWEEK...WITH A SERIES OF UPPER LEVEL DISTURBANCES ALSO ROTATING ACROSS THE REGION. && .SHORT TERM (THROUGH 06Z WEDNESDAY)...THE COLD FRONT THAT PUSHED THROUGH NORTHERN AND CENTRAL UTAH OVERNIGHT IS NOW NEAR A KDRA- KGJT LINE. CONDITIONS ARE CLEAR BEHIND THE FRONT WITH MAXES RUNNING 5-10F BELOW WHAT WAS OBSERVED YESTERDAY...A FEW DEGREES BELOW CLIMO. OVER SOUTHERN UTAH...ISOLATED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED PRIMARILY ALONG THE FRONTAL BOUNDARY. CONVECTION IS PROGGED TO CONTINUE THROUGH THE EARLY EVENING BEFORE DISSIPATING WITH THE LOSS OF DAYTIME HEATING. HIGH PRESSURE HAS STARTED TO BUILD BACK OVER THE FORECAST AREA AND WILL CONTINUE TO DO SO OVER THE NEXT FEW DAYS...RESULTING IN A WARMING TREND WITH LIGHT WINDS. BY TOMORROW AFTERNOON...THE FLOW IS PROGGED TO FLIP TO MORE OF A SOUTHERLY DIRECTION...ALLOWING THE RELATIVELY MOIST AIR OVER SOUTHERN UTAH TO ADVECT INTO NORTHERN UTAH. AS A RESULT...THERE WILL BE A THREAT OF ISOLATED CONVECTION OVER THE HIGHER TERRAIN OF ALL OF UTAH...AS OPPOSED TO JUST THE SOUTHERN HALF. BY MONDAY...THE FLOW IS EXPECTED TO BECOME MORE WESTERLY...TEMPORARILY DRAWING DRIER AIR BACK INTO THE AREA. GFS/EC STILL INDICATING THE BEGINNING OF A MONSOONAL PUSH ON TUESDAY...THOUGH THEY ARE STILL SLOWER WITH THE TIMING. AS A RESULT...HAVE TRIMMED POPS BACK JUST A BIT FOR TUESDAY MORNING AND TUESDAY AFTERNOON. .LONG TERM (AFT 06Z WEDNESDAY)...A SOUTHERLY FLOW WILL CONTINUE TO PUSH MOISTURE NORTHWARD ACROSS THE REGION WEDNESDAY AND WEDNESDAY NIGHT...WITH PRECIPITABLE WATER VALUES INCREASING TO NEAR THREE QUARTERS OF AN INCH NORTHWEST TO INCH AND A QUARTER SOUTHEAST. GFS AND ECMWF IN GENERAL AGREEMENT WITH ROTATING A SERIES OF UPPER LEVEL DISTURBANCES AROUND RIDGE THROUGH FORECAST AREA...THOUGH ECMWF FEATURES DISPLACED A BIT FARTHER NORTH AND WEST AND A BIT SLOWER THAN GFS. GIVE AMPLE MOISTURE AND UPWARD FORCING...WILL CONTINUE WITH SLIGHT CHANCE TO CHANCE WORDING STATEWIDE THROUGH WEDNESDAY NIGHT. MODELS SUGGEST FLOW TURNING WESTERLY ON THURSDAY...LEADING TO A SLOW DRYING OF THE AIR MASS. THUS...STILL EXPECT A CHANCE FOR SHOWERS AND THUNDERSTORMS ON THURSDAY...ESPECIALLY EASTERN AND SOUTHERN SECTIONS OF FORECAST AREA. BY FRIDAY...COVERAGE SHOULD BE MORE TERRAIN BASED...WITH EVEN LESS ACTIVITY ACROSS THE HIGHER TERRAIN ON SATURDAY. WITH DECREASING CLOUD COVER AND WARMING TEMPERATURE ALOFT...SHOULD SEE READINGS BACK INTO THE LOWER 90S BY NEXT WEEKEND. && .AVIATION...WINDS AT THE SLC TERMINAL ARE EXPECTED TO SWITCH TO THE SOUTHEAST BETWEEN 03Z AND 05Z. SMOKE WILL PERSIST ACROSS THE AREA THROUGH THE NEXT COUPLE DAYS...WITH VISIBILITIES GENERALLY REMAINING IN THE 6 TO 10 MILE RANGE. && .FIRE WEATHER...A DRY COLD FRONT HAS MOVED INTO SOUTHERN UTAH THIS AFTERNOON...RESULTING IN A NOTICEABLE COOLDOWN IN TEMPERATURES ACROSS NORTHERN AND CENTRAL UTAH. HIGH PRESSURE BUILDING OVER THE AREA THROUGH EARLY NEXT WEEK WILL ALLOW THE TEMPERATURES TO QUICKLY REBOUND AS WINDS REMAIN GENERALLY LIGHT. DRY CONDITIONS CONTINUE OVER NORTHERN UTAH WHILE SOME MOISTURE LINGERS OVER CENTRAL AND SOUTHERN UTAH. THE FRONT WILL ACT AS A FOCUS FOR ISOLATED SHOWERS AND THUNDERSTORMS THROUGH THE EARLY EVENING. THE MOISTURE WILL SPREAD NORTHWARD TOMORROW...SO THE THREAT OF CONVECTION WILL SPREAD INTO THE HIGHER TERRAIN OF NORTHERN UTAH. DRIER AIR WILL MOVE IN FOR MONDAY BEFORE MONSOONAL MOISTURE MOVES IN FOR THE MIDDLE OF THE UPCOMING WEEK. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...NONE. WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING WYZ277. && PUBLIC...TRAPHAGAN/BARJENBRUCH AVIATION...SCHOENING FIRE WEATHER...TRAPHAGAN 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 245 AM MDT SAT AUG 22 2015 UTZ001>016-019>021-517-518-WYZ021-231300- 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- 245 AM MDT SAT AUG 22 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN TWO THIRDS OF UTAH AND SOUTHWEST WYOMING. .DAY ONE...TODAY AND TONIGHT THE COMBINATION OF GUSTY WINDS AND LOW HUMIDITY WILL SUPPORT CRITICAL FIRE WEATHER CONDITIONS ACROSS SOUTHWEST WYOMING INTO THIS EVENING. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY THE NEXT SURGE OF MONSOONAL MOISTURE IMPACTS THE REGION MID WEEK. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. ROGOWSKI/KRUSE FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/SALTLAKECITY/ (ALL LOWER CASE) FOR INFORMATION ON POTENTIAL ROAD TRAVEL IMPACTS VISIT... HTTP://WWW.UDOTTRAFFIC.UTAH.GOV/ROADWEATHERFORECAST.ASPX
The Cedar City radar (KICX), 161 km away, was scanning. The volume nearest the first event began at 22:16 UTC.
1 flash flood. Local standard time, as filed.
Park rangers at Capitol Reef National Park reported flash flooding at multiple locations in the park. Flooding first occurred along Sulphur Creek, and then a second thunderstorm initiated flash flooding along Grand Wash, with flood waters reaching Highway 24.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2015Every state in 2015This day in weather historyWarnings in Utah, August 2015
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: 599450.