Heavy rainfall from thunderstorms produced flash flooding across portions of the Squirrel Creek burn scar in southwest Albany County.
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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 CYS wrote it up.
Heavy rainfall from thunderstorms produced flash flooding across portions of the Squirrel Creek burn scar in southwest Albany County.
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 Cheyenne, WY wrote its last area forecast discussion before the first event at Sep 12, 4:38 PM MST, 37 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHEYENNE WY 538 PM MDT THU SEP 12 2013 .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 413 PM MDT THU SEP 12 2013 REX BLOCK OVER WESTERN NOAM WILL KEEP THE PATTERN SLOW TO CHANGE INTO THE UPCOMING WEEKEND. UPPER LOW WILL CONTINUE TO WEAKEN AS IT SLOWLY LIFTS NORTH TOWARDS IDAHO AT THE PALTRY RATE OF 5-10 MPH. AHEAD OF THIS LOW...THE WARM CONVEYER BELT CONTINUES TO BE IN FULL EFFECT ALONG THE FRONT RANGE. 12Z RAOBS SHOWED PWATS RUNNING 200%+ OF NORMAL WITHIN THIS MOISTURE FETCH. BENEATH THIS...KCYS VAD SHOWS 20 KNOTS OF EASTERLY LLVL UPSLOPE FEEDING 55F+ DEW POINT AIR PERPENDICULAR TO THE TERRAIN. IMPRESSIVE DIFFLUENT FLOW ALOFT FURTHER AIDING RAINFALL EFFICIENCY. LATEST KCYS 88D RETURNS SHOWING AREA OF MODERATE RAINFALL TRAINING ALONG THE SOUTHERN LARAMIE RANGE ALONG WITH ADDITIONAL DEVELOPMENT ALONG THE COLORADO FRONT RANGE. THIS ACTIVITY IS FORMING AHEAD OF SHORTWAVE LIFTING NORTH THROUGH SOUTHERN COLORADO. SO...EXPECT RAIN SHOWERS TO BE NUMEROUS THROUGH THE OVERNIGHT HOURS...WITH BEST COVERAGE CONFINED TO THE SOUTHEAST WYOMING MOUNTAIN AND ADJACENT FOOTHILL LOCATIONS. AN ADDITIONAL 1 TO 3 INCHES OF RAINFALL REMAINS IN THE CARDS FROM THIS ACTIVITY. WITH RECENT RAINFALL AMOUNTS OF 3 TO 4 INCHES FALLING ALONG THE SOUTHERN LARAMIE RANGE...FEEL THE BEST FLASH FLOOD THREAT TO BE CONFINED THERE. ALSO HAVE CONCERNS ABOUT THE SQUIRREL CREEK BURN SCAR NR WOODS LANDING. THE FLASH FLOOD WATCH CONTINUES TO BE IN EFFECT UNTIL MIDNIGHT FOR THE SNOWY RANGE AS WELL AS THE SOUTHERN LARAMIE RANGE AND ADJACENT EASTERN FOOTHILLS. UPPER LOW WILL BECOME MUCH MORE LOOSELY ORGANIZED ON FRIDAY AS IT SLOWLY TRACKS THROUGH THE CENTRAL ROCKIES. THE AFOREMENTIONED SHORTWAVE WILL MOVE THROUGH THE AREA ON FRIDAY MORNING. THIS WILL LIKELY ENHANCE PRECIPITATION AS IT MOVES THROUGH THE AREA. THE NAM HAS ITS GREATEST IMPACT FURTHER EAST ACROSS THE WESTERN NEBRASKA PANHANDLE...WITH THE GFS FURTHER WEST ACROSS SOUTHEAST WYOMING. FOR NOW HAVE TAILORED THE FORECAST TO ACCOUNT FOR BOTH SCENARIOS AND WILL REFINE LATER. PROGD SBCAPES ON FRIDAY WILL RISE TO BETWEEN 400 AND 600 J/KG SO MAY SEE MORE CONVECTIVE ELEMENTS COMPARED TO TODAY. BEST PLUME OF MID-LEVEL MOISTURE WILL CONTINUE TO SHIFT EAST ON SATURDAY. EVEN SO...WITH THE WEAKENING UPPER-LOW PASSING OVERHEAD EXPECT A CONTINUATION OF UNSETTLED CONDITIONS. AGAIN WITH SLIGHTLY MORE CONVECTIVE COVERAGE COMPARED TO FRIDAY. AS FOR TEMPERATURES...FRIDAY WILL BE THE COOLEST DAY OF THE PERIOD WITH LIMITED INSOLATION BENEATH A THICK CLOUD CANOPY. HIGHS WILL ONLY REACH THE 60S AT MOST LOCATIONS. EXPECT MORE BREAKS IN THE CLOUDS ON SATURDAY...EXPECT SLIGHTLY WARM CONDITIONS ESPECIALLY ACROSS THE WESTERN NEBRASKA PANHANDLE WHERE HIGHS ARE EXPECTED TO REACH INTO THE 80S. .LONG TERM...(SUNDAY THROUGH THURSDAY) ISSUED AT 413 PM MDT THU SEP 12 2013 REMNANTS OF THE UPPER LOW EXPECTED TO FINALLY MOVE ACROSS THE REGION SUNDAY KEEPING CHANCES FOR SHOWERS AND A FEW STORMS GOING...THOUGH ON A MORE SCATTERED BASIS...AIDED BY CONTINUING SFC UPSLOPE FLOW. LEE TROFFING DEVELOPS OVER THE HIGH PLAINS EARLY MONDAY AS THE UPPER FLOW TURNS MORE WESTERLY WITH THIS SFC TROF THEN PROGRESSING EASTWARD MONDAY NIGHT WITH ISOLATED CONVECTION POSSIBLE WITH IT. SFC FLOW WILL TURN DOWNSLOPE BEHIND THIS TROF AND ALLOW FOR A DRIER AND WARMER WEATHER REGIME TO SET UP OVER THE CWA FOR TUESDAY THROUGH THURSDAY. COULD GET QUITE BREEZY OVER WESTERN PARTS OF THE CWA WEDS AND THURSDAY AS A RATHER FAST WSW FLOW SETS UP. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY AFTERNOON) ISSUED AT 535 PM MDT THU SEP 12 2013 SHOWERS AND ISOLATED THUNDERSTORMS TO BECOME MORE WIDESPREAD THIS EVENING AS ENERGY FROM AN UPPER LEVEL LOW CURRENTLY OVER UTAH GETS SPUN OFF AND MOVES THROUGH SOUTHEAST WYOMING. PERSISTENT SOUTHEAST UPSLOPING WINDS WILL KEEP IFR CONDITIONS ALONG THE EAST SLOPES OF THE SOUTHERN LARAMIE RANGE...EVENTUALLY SPREADING OUT INTO THE SOUTHERN PANHANDLE AFTER 06Z. THESE LOW CONDITIONS ARE EXPECTED TO CONTINUE THROUGH AT LEAST 18Z FRIDAY. && .FIRE WEATHER... ISSUED AT 413 PM MDT THU SEP 12 2013 LOW MOVING UPPER LOW AND RESULTANT VERY MOIST CONDITIONS WILL SUPPRESS ANY FIRE WEATHER CONCERNS FOR THE FORESEEABLE FUTURE. THE PATTERN WILL TURN WARMER...DRIER AND BREEZIER NEXT WEEK. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR WYZ114-116-117. NE...NONE. && SHORT TERM...HAHN LONG TERM...RE AVIATION...CLAYCOMB FIRE WEATHER...HAHN
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 1136 AM MDT THU SEP 12 2013 WYZ103-106-107-114>118-131745- NORTH LARAMIE RANGE- CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY- EAST PLATTE COUNTY-SNOWY RANGE-LARAMIE VALLEY-SOUTH LARAMIE RANGE- SOUTH LARAMIE RANGE FOOTHILLS-CENTRAL LARAMIE COUNTY- 1136 AM MDT THU SEP 12 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST WYOMING. .DAY ONE...THIS AFTERNOON AND TONIGHT WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TODAY WITH MODERATE TO LOCALLY HEAVY RAIN POSSIBLE LATE THIS AFTERNOON THROUGH TONIGHT. LOCALIZED FLOODING IS POSSIBLE ALONG THE SOUTHERN LARAMIE RANGE...EASTERN LARAMIE RANGE FOOTHILLS...AND IN THE SNOWY RANGE. A FLASH FLOOD WATCH IS IN EFFECT FOR THIS AREA FROM NOON TODAY THROUGH MIDNIGHT TONIGHT. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THE UNSETTLED WEATHER PATTERN WILL CONTINUE FOR THE REST OF THE WEEK AND INTO THE WEEKEND...BRINGING MODERATE TO LOCALLY HEAVY RAIN AT TIMES WITH ISOLATED AFTERNOON THUNDERSTORMS. .SPOTTER INFORMATION STATEMENT... PLEASE REPORT FLOODING OR MUDSLIDE INFORMATION TO THE NATIONAL WEATHER SERVICE OFFICE IN CHEYENNE AT 1-800-269-6220. && THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT... HTTP://WEATHER.GOV/CHEYENNE NEZ002-003-019>021-054-055-095-096-WYZ101-102-104-105-108>113-119- 131745- DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE- NORTH SIOUX-SOUTH SIOUX-CONVERSE COUNTY LOWER ELEVATIONS- NIOBRARA COUNTY-FERRIS/SEMINOE/SHIRLEY MOUNTAINS-SHIRLEY BASIN- GOSHEN COUNTY-CENTRAL CARBON COUNTY-NORTH SNOWY RANGE FOOTHILLS- SOUTHWEST CARBON COUNTY-SIERRA MADRE RANGE- UPPER NORTH PLATTE RIVER BASIN-EAST LARAMIE COUNTY- 1136 AM MDT THU SEP 12 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA PANHANDLE...EAST CENTRAL WYOMING...SOUTH CENTRAL WYOMING AND SOUTHEAST WYOMING. .DAY ONE...THIS AFTERNOON AND TONIGHT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED AGAIN THIS AFTERNOON...WITH THE BEST CHANCE MAINLY SOUTH OF THE NORTH PLATTE RIVER VALLEY. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THE UNSETTLED WEATHER PATTERN WILL CONTINUE FOR THE REST OF THE WEEK AND INTO THE WEEKEND WITH SCATTERED SHOWERS AND ISOLATED AFTERNOON THUNDERSTORMS EXPECTED ACROSS MUCH OF THE NEBRASKA PANHANDLE. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. && THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT... HTTP://WEATHER.GOV/CHEYENNE
The Cheyenne radar (KCYS), 101 km away, was scanning. The volume nearest the first event began at 00:13 UTC.
1 flash flood. Local standard time, as filed.
Two to three inches of rain in a 90-minute period flooded Highway 311/47. Several area streams in central and southern portions of the Squirrel Creek burn scar were running bankfull.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2013Every state in 2013This day in weather historyWarnings in Wyoming, September 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: 469303.