Abundant monsoonal moisture combined with daytime heating to generate heavy rain producing thunderstorms.
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 GJT wrote it up.
Abundant monsoonal moisture combined with daytime heating to generate heavy rain producing thunderstorms.
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 Jul 27, 12:53 PM MST, 1 hour 41 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 153 PM MDT TUE JUL 27 2010 ...MONSOONAL BURST EXPECTED TO LAST THROUGH THE END OF THE WEEK... .SHORT TERM...TONIGHT THROUGH THURSDAY... AS DISCUSSED PREVIOUSLY...HIGH PRESSURE HAS SHIFTED EASTWARD WHICH HAS OPENED THE DOOR TO A SURGE OF DEEP SUBTROPICAL MOISTURE FROM THE SOUTH AND SOUTHWEST. IN RESPONSE...MOISTURE ACROSS THE AREA HAS INCREASED MARKEDLY WITH DEW POINTS OVER THE NORTH UP FROM 5 TO 10 DEGS F TO NEAR 50 DEGS F. THE CENTRAL ZONES HAD DEW POINTS IN THE LOWER TO MID 50S WITH VALUES NEAR 60 DEGS F ACROSS THE SOUTH. DEBRIS CLOUDS FROM THE DISTURBANCE WHICH MOVED OVER THE AREA EARLY THIS MORNING HAVE HELD BACK STORMS OVER THE CENTRAL MOUNTAINS WHILE...IN CONTRAST...STORMS HAVE ERUPTED IN THE LATE MORNING AND EARLY AFTERNOON OVER THE SOUTHERN MOUNTAINS WHERE SKIES WERE MOSTLY CLEAR THROUGH MUCH OF THE DAY SO FAR. LIGHT STEERING FLOW...COMBINED WITH PW VALUES OVER AN INCH....SATURATED SOILS AND A WEAK SHORTWAVE MOVING INTO THE AREA FROM NORTHEAST ARIZONA ACROSS THE SOUTH CONTINUES TO BE AN ISSUE FOR SOUTHWEST COLORADO AND SOUTHEAST UTAH...SO WILL CONTINUE THE FLASH FLOOD WATCH. THOUGH WEAKENING...THE PREVIOUSLY MENTIONED SHORTWAVE ENERGY OVER THE FOUR CORNERS REGION SHOULD CONTINUE TO AFFECT SOUTHEAST UTAH AND SOUTHWEST COLORADO LATER TONIGHT...SO BOOSTED POPS OVER THE AREA. VERY LITTLE CHANGE EXPECTED WEDNESDAY AND THURSDAY...THOUGH MOISTURE WILL DEEPEN ACROSS THE NORTH AS MONSOONAL SURGE CONTINUES. MODEL GUIDANCE SHOWED NEAR NORMAL HIGHS AND LOWS THROUGH THE PERIOD WHICH APPEARED REASONABLE GIVEN THE CURRENT WEATHER REGIME. .LONG TERM...THURSDAY NIGHT THROUGH TUESDAY... LITTLE CHANGE SEEN IN THE OVERALL SYNOPTIC PATTERN THIS LONG TERM PERIOD...WITH A TROF ALONG THE WEST COAST WHILE HIGH PRESSURE REMAINS OVER TX/OK. THIS PRODUCES A VERY STRONG MONSOONAL SIGNATURE OVER THE SWRN STATES. THIS WILL RESULT IN A MOIST SOUTHWESTERLY FLOW OVER OUR CWA WITH PCP WTR VALUES MOSTLY IN EXCESS OF 1 INCH. LITTLE DAY TO DAY CHANGE SEEN IN THE MODELS AND SUSPECT THE AMOUNT AND STRENGTH OF CONVECTIVE ACTIVITY WILL DEPEND ON THE DEGREE OF CLOUD COVER AND EMBEDDED SHRT WVS...WITH THE LATTER BEING MOST SIGNIFICANT. LIGHT WINDS ALOFT WILL MEAN STORMS WILL BE SLOW MOVING RESULTING IN A POTENTIAL FOR LOCALLY HEAVY RAINFALL. TEMPERATURES WILL RUN NEAR TO SLIGHTLY BELOW SEASONAL NORMALS. && .AVIATION... EXPECT SCATTERED THUNDERSTORMS TO PERSIST OVER MOUNTAINS AREAS LATE THIS AFTERNOON...AND CONTINUING INTO THE EVENING. STORMS WILL CREATE AREAS OF MOUNTAIN OBSCURATIONS WITH MVFR CIGS AND VSBY IN RAIN SHOWERS. LOCALIZED IFR CIGS AND VSBY ARE LIKELY IN THE SAN JUAN...LA SAL AND ABAJO MOUNTAINS AND THE LOWER ELEVATIONS OF THE FOUR CORNERS AREA DUE TO HEAVY RAINFALL. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE UT...NONE. SHORT TERM.....NL LONG TERM......MC AVIATION.......TGJT
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 545 AM MDT TUE JUL 27 2010 COZ001>014-017>023-UTZ022>025-027>029-281145- ANIMAS RIVER BASIN-ARCHES/GRAND FLAT-CANYONLANDS/NATURAL BRIDGES- CENTRAL COLORADO RIVER BASIN- CENTRAL GUNNISON AND UNCOMPAHGRE RIVER BASIN- CENTRAL YAMPA RIVER BASIN-DEBEQUE TO SILT CORRIDOR- EASTERN UINTA BASIN-EASTERN UINTA MOUNTAINS- ELKHEAD AND PARK MOUNTAINS-FLAT TOPS- FOUR CORNERS/UPPER DOLORES RIVER- GORE AND ELK MOUNTAINS/CENTRAL MOUNTAINS-GRAND AND BATTLEMENT MESAS- GRAND VALLEY-LA SAL AND ABAJO MOUNTAINS-LOWER YAMPA RIVER BASIN- NORTHWEST SAN JUAN MOUNTAINS-PARADOX VALLEY/LOWER DOLORES RIVER- ROAN AND TAVAPUTS PLATEAUS-SAN JUAN RIVER BASIN-SOUTHEAST UTAH- SOUTHWEST SAN JUAN MOUNTAINS-TAVAPUTS PLATEAU- UNCOMPAHGRE PLATEAU AND DALLAS DIVIDE-UPPER GUNNISON RIVER VALLEY- UPPER YAMPA RIVER BASIN-WEST ELK AND SAWATCH MOUNTAINS- 545 AM MDT TUE JUL 27 2010 ...FLASH FLOOD WATCH IN EFFECT THIS AFTERNOON AND EVENING FOR SOUTHEAST UTAH AND SOUTHWEST COLORADO... THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS MUCH OF WESTERN COLORADO AND EASTERN UTAH THROUGH TONIGHT. THE STRONGEST THUNDERSTORMS WILL PRODUCE SMALL HAIL...GUSTY WINDS TO 50 MPH AND VERY HEAVY RAINFALL. THE HEAVY RAINFALL WILL LEAD TO THE POSSIBILITY OF FLASH FLOODING...ESPECIALLY ACROSS THE SAN JUAN MOUNTAINS IN SOUTHWEST COLORADO AND NEAR NARROW SLOT CANYONS ACROSS SOUTHEAST UTAH. AS A RESULT...A FLASH FLOOD WATCH HAS BEEN ISSUED FOR THESE AREAS FOR THIS AFTERNOON AND EVENING. PLEASE SEE THE GRAND JUNCTION NATIONAL WEATHER SERVICE WEB SITE AT HTTP://WEATHER.GOV/GJT FOR THE LATEST INFORMATION. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH TUESDAY DEEP MONSOONAL FLOW INTO UTAH AND COLORADO WILL CONTINUE THROUGH EARLY THIS WEEKEND. THIS WILL BRING NUMEROUS SHOWERS AND THUNDERSTORMS WITH LOCALLY HEAVY RAINS. THE POTENTIAL EXISTS FOR LOCALIZED FLASH FLOODING EACH AFTERNOON AND EVENING THROUGH SATURDAY. SUNDAY AND MONDAY...MONSOONAL FLOW WEAKENS BUT SUFFICIENT MOISTURE FOR SCATTERED SHOWERS AND THUNDERSTORMS EACH AFTERNOON AND EARLY EVENING WILL REMAIN. LOCALLY HEAVY RAIN WILL STILL BE POSSIBLE. .SPOTTER INFORMATION STATEMENT SPOTTER ACTIVATION IS POSSIBLE IN SOME AREAS TODAY. REPORTS OF SIGNIFICANT WEATHER WILL AGAIN BE APPRECIATED. JDC
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1043 AM MDT TUE JUL 27 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1245 AM HEAVY RAIN 1 NE MONTROSE 38.49N 107.86W
07/27/2010 M1.18 INCH MONTROSE CO TRAINED SPOTTER
1.18 INCHES OF RAIN IN 30 MINUTES FROM 1245AM THROUGH
115AM.
&&
EVENT NUMBER GJT1000634
MALEKSAPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1046 AM MDT TUE JUL 27 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1245 AM TSTM WND DMG 1 NE MONTROSE 38.49N 107.86W
07/27/2010 MONTROSE CO TRAINED SPOTTER
IN ADDITION TO 1.18 INCHES OF HEAVY RAIN IN 30
MINUTES... WIND GUSTS BROKE SOME TREE LIMBS AND KNOCKED
OVER AN 18 INCH DIAMETER COTTONWOOD TREE IN RIVERSIDE
PARK NEAR MONTROSE. NO MOBILE HOMES WERE IMPACTED.
&&
EVENT NUMBER GJT1000635
MALEKSASPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GRAND JUNCTION CO 130 PM MDT TUE JUL 27 2010 COZ017-272015- UNCOMPAHGRE PLATEAU/DALLAS DIVIDE CO- 130 PM MDT TUE JUL 27 2010 ...SIGNIFICANT WEATHER ADVISORY FOR WESTERN MESA COUNTY UNTIL 215 PM MDT... AT 125 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM EXTENDING FROM 5 MILES WEST TO 8 MILES SOUTHWEST OF GLADE PARK. THIS STORM WAS NEARLY STATIONARY. HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT DANGEROUS LIGHTNING. LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE... MAINLY RURAL AREAS OF WESTERN MESA COUNTY WEST OF GLADE PARK ON THE UNCOMPAGHRE PLATEAU. MDA
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GRAND JUNCTION CO 152 PM MDT TUE JUL 27 2010 UTZ028-272030- LA SAL AND ABAJO MOUNTAINS UT- 152 PM MDT TUE JUL 27 2010 ...SIGNIFICANT WEATHER ADVISORY FOR EASTERN SAN JUAN COUNTY UNTIL 230 PM MDT... AT 150 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 7 MILES NORTHEAST OF MONTICELLO...MOVING SOUTHWEST AT 10 MPH. HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT DANGEROUS LIGHTNING. LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE... MONTICELLO...AND THE MONTICELLO ARPT. MDA/NL
The Grand Junction radar (KGJX), 104 km away, was scanning. The volume nearest the first event began at 21:34 UTC.
2 flash flood, 1 heavy rain. Local standard time, as filed.
Heavy rainfall near Norwood caused mudslides to rush over Highway 145 between Norwood and Placerville. A storm spotter in Norwood measured 0.75 of an inch of rain within 15 minutes. Highway 145 was closed for a period of time due to the debris on the road.
An access road to Highway 141 was washed out in one spot due to runoff from heavy rainfall.
Heavy rainfall caused flash flooding in the area of Dexter Creek and Skyrocket Creek north of Ouray, as well as along Cascade Creek in Ouray. In some sections of Dexter Creek, the flash flood waters were nearly 20 feet deep. A section of road was washed out and the remaining buildings from the abandoned Old Maid Mine and town, built in the late 1800s, were completely obliterated with only some foundations remaining. An enormous amount of debris flowed through and collected in sections of Dexter Creek, which is the main water source for many residents in Ouray County. In particular, log jams and boulders the size of large trucks clogged a quarter-mile section of Dexter Creek, filling the creek up to 20 feet deep from the original creek bed elevation. Skyrocket Creek flowed up to a foot deep across Highway 550 as the highway culvert was filled beyond capacity. A motel on the west side of the highway experienced flooding in the parking lot and to some lower level motel rooms. Skyrocket Creek deposited about 8000 cubic yards of debris, mostly rocks and boulders, in a catch basin just above the Uncompahgre River. About 2000 cubic yards of debris filled up a catch basin near Highway 550 just before Cascade Creek dumps into the Uncompahgre River. The Uncompahgre River gage near Ridgway measured a stage jump of nearly 2 feet that evening due to the upstream inflow from the flooding creeks. Radar storm total rainfall estimates over the mountains near Ouray ranged from 1.5 to 1.75 inches, most of which fell within 60 minutes.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2010Every state in 2010This day in weather historyWarnings in Colorado, July 2010
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: 249983, 257608, 257691.