Showers and thunderstorms increased across Utah on September 20 and 21, with both severe thunderstorms and flash flooding reported during these two days.
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 increased across Utah on September 20 and 21, with both severe thunderstorms and flash flooding reported during these two days.
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 Sep 20, 9:17 AM MST, 4 hours 43 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 1017 AM MDT SAT SEP 20 2014 .SYNOPSIS...AN UPPER LEVEL LOW PRESSURE SYSTEM ALONG THE SOUTHERN CALIFORNIA COAST WILL LIFT NORTHEAST INTO THE THEN ACROSS THE GREAT BASIN SUNDAY THROUGH EARLY MONDAY. HIGH PRESSURE WILL FOLLOW FOR MID WEEK. && .DISCUSSION...THE UPPER LOW CURRENTLY POSITIONED ALONG THE SOUTHERN CALIFORNIA COAST WILL BEGIN TO TRACK NORTHEAST THIS AFTERNOON. THIS FEATURE WILL CONTINUE ON A NORTHEAST INTO THE WESTERN GREAT BASIN EARLY SUNDAY...REACHING NORTHERN UTAH SUNDAY EVENING. THE UPPER LOW WILL TAKE A TURN TO THE EAST AS IT EXITS THE REGION LATE SUNDAY NIGHT/EARLY MONDAY. HEIGHTS WILL BEGIN TO BUILD BEHIND THE EXITING LOW...WITH A STRONG UPPER RIDGE CENTERED ACROSS THE EASTERN GREAT BASIN MIDWEEK. THE STRONGEST CONVECTION ASSOCIATED WITH THE UPPER LOW REMAINS IN THE NORTHEAST FLANK ACROSS SOUTHERN AND WESTERN NEVADA THIS MORNING. CONVECTION REMAINS SOMEWHAT MUTED ACROSS SOUTHWEST UTAH LATE THIS MORNING. CONVECTION WILL PICKUP THROUGH THE AFTERNOON AS GOOD SURFACE HEATING DEVELOPS AND PWAT VALUES RANGE BETWEEN /.75/ AND /1.00/ INCHES. DEEP CONVECTION MAY STRUGGLE TO DEVELOP THIS AFTERNOON AS MID-LEVEL TEMPS REMAIN STATIC AND INHIBIT DEEP LAYER INSTABILITY. SHOWERS/THUNDERSTORMS SHOULD INCREASE DRAMATICALLY TONIGHT AS THE UPPER LOW ADVANCING INTO THE WESTERN GREAT BASIN. THE GREATEST CONCENTRATION OF CONVECTION SHOULD REMAIN IN THE NORTHEAST FLANK OF THE LOW...WITH WESTERN UTAH IN LINE FOR SCATTERED SHOWERS AND STORMS THIS EVENING. NORTHERN UTAH WILL BECOME THE FOCUS FOR PRECIP LATE TONIGHT/EARLY MONDAY AS THE CENTER OF THE UPPER LOW MOVES EAST-NORTHEAST THROUGH EXTREME NORTHERN UTAH. MOST PRECIP SHOULD TAPER OFF DURING THE AFTERNOON...WITH ONE QUICK SHOT OF ADDITIONAL SHOWERS ALONG A TRAILING SHORTWAVE MONDAY EVENING. BUILDING HEIGHTS IN THE WAKE OF THE EXITING UPPER LOW WILL EVENTUALLY FORM A VERY STRONG UPPER RIDGE EXTENDING FORM THE NORTHERN PLAINS TO THE DESERT SOUTHWEST MIDWEEK. UNSEASONABLY WARM TEMPS AND BONE DRY CONDITIONS WILL EXISTS THROUGH AT LEAST THURSDAY...FOLLOWED BY A NEW AND FAIRLY STRONG PACIFIC TROUGH SCHEDULED TO REACH THE WESTERN GREAT BASIN BY THE END OF THE WEEK. && .FIRE WEATHER...MOISTURE RETURNS NORTH TODAY ACROSS SOUTHERN UTAH...PROMPTING SCATTERED CONVECTION WHICH MAY BRING LOCALLY HEAVY RAINFALL IN ADDITION TO CLOUD TO GROUND LIGHTNING. THIS ACTIVITY IS FORECAST TO SPREAD INTO CENTRAL UTAH TONIGHT AND NORTHERN UTAH SUNDAY. SUNDAY WILL SEE THE MOST WIDESPREAD CHANCE OF RAINFALL AS A WEAKENING STORM SYSTEM CROSSES THE EASTERN GREAT BASIN. THIS PATTERN WILL BRING MORE EXPANSIVE CLOUD COVER...RISING HUMIDITY LEVELS AND COOLING TEMPERATURES. CONVECTION LINGERS MONDAY ACROSS THE NORTH AND EAST...DECAYING FOR GOOD MONDAY EVENING. A WARMING AND DRYING TREND WILL BEGIN MONDAY ACROSS THE SOUTH AND BE IN PLACE ACROSS THE ENTIRE REGION THROUGH MID WEEK AS A RIDGE OF HIGH PRESSURE AMPLIFIES OVERHEAD. THERE REMAINS SIGNIFICANT UNCERTAINTY REGARDING THE TIMING OF A STRONG COLD FRONT LATE IN THE WEEK. CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE AHEAD OF THE COLD FRONT WITH STRONG GUSTY SOUTH WINDS DEVELOPING...BEFORE CONVECTIVE CHANCES ONCE AGAIN INCREASE NEXT WEEKEND. && .AVIATION...VFR CONDITIONS WILL PREVAIL THROUGH THE VALID TAF PERIOD AT THE SLC TERMINAL...THOUGH A CEILING ABOVE 8000 FT CAN BE ANTICIPATED NEAR THE END OF THE TAF PERIOD WHEN THE CHANCE FOR SHOWERS AND AN EMBEDDED THUNDERSTORM SIGNIFICANTLY INCREASE SUNDAY MORNING. A LIGHT SOUTHEASTERLY DRAINAGE WIND WILL SHIFT TO A NORTHWEST FLOW LAKE BREEZE A BIT EARLIER TODAY...AROUND MIDDAY...DUE TO A NORTHERLY PRESSURE GRADIENT IN PLACE. A SOUTHEAST DRAINAGE WIND WILL DEVELOP AGAIN TONIGHT AND SHOULD BE ENHANCED A BIT BY A DEVELOPING EASTERLY FLOW ALOFT. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...NONE. WY...NONE. && PUBLIC...CONGER FIRE WEATHER/AVIATION...ROGOWSKI 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 513 AM MDT SAT SEP 20 2014 UTZ001>016-019>021-517-518-WYZ021-211200- 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- 513 AM MDT SAT SEP 20 2014 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN TWO THIRDS OF UTAH AND SOUTHWEST WYOMING. .DAY ONE...TODAY AND TONIGHT SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER THE SOUTHWESTERN OUTLOOK AREA THIS AFTERNOON...THEN WILL SPREAD ACROSS ABOUT THE SOUTHERN TWO THIRDS OF THE AREA TONIGHT. LOCAL HEAVY RAINFALL WILL BE POSSIBLE WITH THESE STORMS. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY SHOWERS AND THUNDERSTORMS WILL SPREAD NORTH ACROSS THE REMAINDER OF THE OUTLOOK AREA BY MIDDAY SUNDAY AND CONTINUE ACROSS MOST OF THE AREA SUNDAY AFTERNOON. STORMS WILL BEGIN TO TAPER OFF FROM THE SOUTHWEST SUNDAY NIGHT AND END MONDAY EVENING. LOCAL HEAVY RAINFALL WILL CONTINUE TO BE POSSIBLE WITH THESE STORMS. WARM DRY CONDITIONS ARE EXPECTED TUESDAY AND WEDNESDAY. SOUTH WINDS WILL DEVELOP THURSDAY AND BECOME GUSTY ACROSS THE WESTERN OUTLOOK AREA THURSDAY AFTERNOON. THESE WINDS WILL SPREAD INTO THE EASTERN OUTLOOK AREA ON FRIDAY AND CONTINUE OVER THE WEST. .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 ROAD TRAVEL IMPACTS VISIT... HTTP://WWW.UDOTTRAFFIC.UTAH.GOV/ROADWEATHERFORECAST.ASPX
The Cedar City radar (KICX), 36 km away, was scanning. The volume nearest the first event began at 21:01 UTC.
2 flash flood, 1 hail, 1 thunderstorm wind. Local standard time, as filed.
Flash flooding was reported in Echo Canyon in Zion National Park.
Golf ball size hail was reported in Cannonville, and the hail ripped through a polycarbonate greenhouse.
In addition to golf ball size hail, the severe thunderstorm moving through Cannonville also had winds strong enough to bend a steel flagpole that was buried in cement.
The severe thunderstorm that caused damage due to hail and wind in Cannonville also flooded several roads through the town.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2014Every state in 2014This day in weather historyWarnings in Utah, September 2014
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: 543278, 543275, 543277, 543279.