Thunderstorms with heavy rainfall moved across the northern Salt Wash basin during the overnight hours of October 12th. The runoff from these storms reached the Delicate Arch area of Arches National Park on October 13th.
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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 GJT wrote it up.
Thunderstorms with heavy rainfall moved across the northern Salt Wash basin during the overnight hours of October 12th. The runoff from these storms reached the Delicate Arch area of Arches National Park on October 13th.
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 Grand Junction, CO wrote its last area forecast discussion before the first event at Oct 13, 11:00 AM MST, 1 hour earlier.
AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE GRAND JUNCTION CO 1200 PM MDT SAT OCT 13 2012 CORRECTED TO REMOVE MENTION OF THE WINTER WEATHER ADVISORY IN THE WATCHES...WARNINGS...ADVISORIES SECTION .UPDATE... ISSUED AT 1155 AM MDT SAT OCT 13 2012 FAVORABLE NORTHWESTERLY FLOW COMBINED WITH MOISTURE WRAPPING AROUND THE STORM SYSTEM OVER THE EASTERN COLORADO PLAINS WILL CONTINUE TO BRING SNOW OFF AND ON THROUGHOUT THE REMAINDER OF THE DAY AND INTO THE EVENING OVER THE NORTHERN AND CENTRAL MOUNTAINS. HOWEVER...ADDITIONAL ACCUMULATIONS WILL BE LIGHT AND THEREFORE... THE WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON WILL BE ALLOWED TO EXPIRE. UPDATE ISSUED AT 727 AM MDT SAT OCT 13 2012 DROPPED WINTER WEATHER ADVISORY FOR THE EASTERN UINTA MOUNTAINS. SATELLITE IMAGERY SHOWED ONLY PATCHY LOW STRATUS CLINGING TO THE EASTERN END OF THE RANGE SO MORE THAN LOCALIZED LIGHT SNOW UNLIKELY. REMAINING WINTER WEATHER ADVISORIES WILL BE ALLOWED TO CONTINUE. UPDATE ISSUED AT 602 AM MDT SAT OCT 13 2012 THE WINTER WEATHER ADVISORY HAS EXPIRED FOR THE GRAND MESA AND THE WEST ELK AND SAWATCH MOUNTAINS...WHILE CONTINUING OVER THE COLORADO NORTHWEST MOUNTAINS. THE CENTER OF THE DEEP LOW CAUSING THIS STORM MOVED EAST OF THE AREA AND NORTHERLY FLOW WILL SPREAD OVER WESTERN CO AND EASTERN UT THROUGHOUT THE DAY. THE TROWAL ENHANCED BAND OF SHOWERS VISIBLE ON SATELLITE AND RADAR OVER NW CO AND NE UT WILL MOVE SOUTH AND EAST TODAY BRINGING A FINAL SPURT OF SNOW TO THE MOUNTAINS AND RAIN TO THE VALLEYS THIS MORNING AND EARLY AFTERNOON. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 415 AM MDT SAT OCT 13 2012 TODAY...THE MODELS ARE HANDLING THIS STORM VERY WELL THIS MORNING. THE 500 MB LOW CENTER IS BEGINNING TO OPEN UP AS IT MOVES OVER CENTRAL CO. WITH THE CIRCULATION DECREASING THE TROWAL SIGNATURE NORTHWEST OF THE LOW IS SHOWING SIGNS OF WEAKENING AS WELL. CLOUD TOPS ARE WARMING AND THE BAND OF ASSOCIATED PRECIPITATION IS THINNING AND DECREASING AS IT MOVE THROUGH NE UT AND EXTREME NW CO. THE TROWAL BAND WILL MOVE OVER NORTHERN AND CENTRAL CO TODAY...GIVING A KICK START TO SNOW OVER THE NORTHERN AND CENTRAL MOUNTAINS SO WILL KEEP THE HEADLINES GOING AS IS. TONIGHT THROUGH SUNDAY... NORTHWEST FLOW WILL DOMINATE TONIGHT AND WILL GIVE WAY TO A RIDGE OF HIGH PRESSURE WHICH WILL BUILD NORTHEAST OVER THE GREAT BASIN ON SUNDAY. A WEAK WAVE WILL DROP ACROSS THE NORTHERN AND CENTRAL MOUNTAINS OF WESTERN COLORADO THIS EVENING AND BRING A CHANCE OF RAIN TO AREAS BELOW 9000 FEET AND SNOW TO AREAS OVER THE HIGHER ELEVATIONS. AN INCH OR TWO OF SNOW MAY FALL AS THIS SYSTEM MOVES THROUGH THIS EVENING. PARTIAL CLEARING WILL OCCUR FROM WEST TO EAST ACROSS THE NORTH OVERNIGHT. DRIER NORTHWEST FLOW WILL DOMINATE ON SUNDAY WITH MOSTLY SUNNY SKIES AND SEASONABLE TEMPERATURES EXPECTED. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 415 AM MDT SAT OCT 13 2012 SUNDAY NIGHT THROUGH FRIDAY... A FLAT RIDGE OF HIGH PRESSURE WILL MOVE OVER THE FORECAST AREA ON SUNDAY NIGHT AND MONDAY. EXPECT DRY CONDITIONS WITH SLIGHTLY WARMER AFTERNOON TEMPERATURES ON MONDAY. MONDAY NIGHT THROUGH FRIDAY...A WEAK SHORTWAVE TROUGH IS PROJECTED TO DEAL A GLANCING BLOW TO THE NORTHERN MOUNTAINS MONDAY NIGHT. ONLY ISOLATED MOUNTAINTOP SHOWERS ARE EXPECTED. ANOTHER STRONGER TROUGH WILL BRING INCREASING NW WINDS ALOFT OVER THE ENTIRE AREA...BUT VERY LITTLE MOISTURE. WILL EXPECTED SCATTERED OROGRAPHIC SNOW SHOWERS OVER THE NORTHERN MTS AND PORTIONS OF THE CENTRAL CO MOUNTAINS TUE NIGHT AND WED...MAINLY ZONES 4/10/13 AND UT 23. THURSDAY AND FRIDAY WILL SEE DRY NORTHWEST FLOW OVER THE AREA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1031 AM MDT SAT OCT 13 2012 MOISTURE WRAPPING AROUND THE STORM SYSTEM OVER THE EASTERN COLORADO PLAINS WILL CONTINUE TO BRING CLOUDS AND SHOWERS TO THE NORTHERN AND CENTRAL MOUNTAINS THIS AFTERNOON. AS A RESULT EXPECT FREQUENT MOUNTAIN OBSCURATIONS EAST OF A KCAG-KRIL-KMTJ-KGUC LINE THROUGH 02Z. AIRPORTS WILL PRIMARILY EXPERIENCE VFR CONDITIONS... THOUGH KSBS...KEGE AND KASE FACE A 30 TO 40 PERCENT CHANCE OF EXPERIENCING MVFR CIGS IN LIGHT RAIN SHOWERS DURING THE AFTERNOON. SCATTERED SNOW SHOWERS WILL CONTINUE OVER THE NORTHERN MOUNTAINS TONIGHT RESULTING IN AREAS OF MOUNTAIN OBSCURATION...OTHERWISE EXPECT VFR CONDITIONS THROUGH 08Z. FROM 08Z TO 15Z SUNDAY...AREAS OF VALLEY FOG IN THE NORTHERN AND CENTRAL VALLEYS COULD RESULT IN MVFR/IFR VSBY AND CIGS WITH LOCALIZED LIFR POSSIBLE. AIRFIELDS POSSIBLY IMPACTED IN KCAG...KRIL...KEGE AND KASE. THE REMAINDER OF THE REGION WILL HAVE VFR CONDITIONS. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && UPDATE...NL SHORT TERM...CC/MPM LONG TERM...CC/MPM AVIATION...NL
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
The Grand Junction radar (KGJX), 119 km away, was scanning. The volume nearest the first event began at 19:00 UTC.
1 flash flood. Local standard time, as filed.
Flash flooding along the Salt Wash inundated the road to Wolf Ranch and closed it for several hours. Many vehicles and tourists were trapped in the Delicate Arch parking area.
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, October 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: 495224.