Heavy rain from a thunderstorm caused flash flooding in Havasu Canyon.
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The episode as NWS FGZ wrote it up.
Heavy rain from a thunderstorm caused flash flooding in Havasu Canyon.
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 Flagstaff, AZ wrote its last area forecast discussion before the first event at Aug 16, 3:15 PM MST, 15 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FLAGSTAFF AZ 315 PM MST MON AUG 16 2010 .SYNOPSIS...EXPECT SHOWER AND THUNDERSTORM ACTIVITY THROUGH WEDNESDAY. SOME STORMS WILL PRODUCE HEAVY RAIN. SLIGHTLY DRIER AIR SHOULD BEGIN TO MAKE ITS WAY ACROSS NORTHERN ARIZONA ON THURSDAY...WITH LOWER CHANCES FOR PRECIPITATION INTO THE WEEKEND. && .DISCUSSION... THIS AFTERNOON...SCATTERED THUNDERSTORMS WERE OCCURRING ACROSS COCONINO AND NORTHERN YAVAPAI COUNTIES. IN APACHE AND NAVAJO COUNTIES THIS MORNINGS CLOUD COVER HAS DECAYED AND THIS AREA SHOULD SEE STORMS DEVELOP THIS AFTERNOON. FROM TONIGHT THROUGH SUNSET WEDNESDAY...NORTHERN ARIZONA WILL HAVE A MOIST AND UNSTABLE AIRMASS OVERHEAD. MID LEVEL WINDS WILL BE VARIABLE AT LESS THAN 15 K) TIL EARLY WED AS ANTICYCLONIC CIRCULATION MOVES EASTWARD OVER OUR AREA. ON WEDNESDAY MORNING...WIND FLOW THROUGH A DEEP LAYER BECOMES SOUTHERLY AS THE ANTICYCLONE CENTER MOVES INTO NEW MEXICO. ADDITIONAL MOISTURE IS FORECAST TO MOVE INTO THE NORTHLAND. CHANGES TO THE PREVIOUS FORECASTS WERE TO INCREASE THE CHANCES FOR SHOWERS AND THUNDERSTORMS AND CLOUD COVER THROUGH SUNSET WEDNESDAY. SOME STORMS TODAY ARE PRODUCING DIME SIZE HAIL AND OR HEAVY RAINFALL THIS AFTERNOON...AND SIMILAR CONDITIONS SHOULD BE EXPECTED THROUGH SUNSET WEDNESDAY. WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...PROGS SHOW LIGHT WESTERLY FLOW ALOFT RETURNING. MOISTURE AND INSTABILITY ARE DECREASING THE MOST OVER AREAS NORTH OF A LINE FROM SELIGMAN THROUGH WINDOW ROCK. AREAS NORTH OF THIS LINE SHOULD BE DRY ON FRIDAY...WHILE AREAS SOUTH OF THE LINE ENJOY A CHANCE OF MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. FOR THE WEEKEND...CURRENT INDICATIONS ARE FOR DEEP LAYERED SOUTHERLY FLOW TO RETURN TO ARIZONA. THUS WE HAVE GONE SLIGHTLY ABOVE CLIMATOLOGICAL POPS FOR THE WEEKEND. && .AVIATION...FOR THE 00Z PACKAGE...SCT TO NUMEROUS THUNDERSTORMS WILL CONTINUE ACROSS NORTHERN AND CENTRAL ARIZONA THIS EVENING...WITH A POSSIBILITY OF ACTIVITY CONTINUING OVERNIGHT IN SOME AREAS. THE STRONGER STORMS WILL BE CAPABLE OF VERY HEAVY RAIN...HAIL...AND WIND GUSTS TO 30KT. FLT CONDITIONS IN THIS ACTIVITY WILL DROP TO MVFR WITH ISOLD IFR IN THE STRONGER CELLS. ADDITIONAL STORMS WILL DEVELOP ON TUESDAY. DISCUSSION NOT UPDATED FOR AMENDMENTS. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && PUBLIC.................DL AVIATION...............JJ VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER INFORMATION.
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE FLAGSTAFF AZ 933 AM MST MON AUG 16 2010 AZZ004>018-037>040-170730- KAIBAB PLATEAU-MARBLE AND GLEN CANYONS-GRAND CANYON COUNTRY- COCONINO PLATEAU-YAVAPAI COUNTY MOUNTAINS- NORTHEAST PLATEAUS AND MESAS HWY 264 NORTHWARD-CHINLE VALLEY- CHUSKA MOUNTAINS AND DEFIANCE PLATEAU- LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTY- LITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTY- LITTLE COLORADO RIVER VALLEY IN APACHE COUNTY- WESTERN MOGOLLON RIM-EASTERN MOGOLLON RIM-WHITE MOUNTAINS- NORTHERN GILA COUNTY-YAVAPAI COUNTY VALLEYS AND BASINS- OAK CREEK AND SYCAMORE CANYONS-BLACK MESA AREA- NORTHEAST PLATEAUS AND MESAS SOUTH OF HWY 264- 929 AM MST MON AUG 16 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL ARIZONA...NORTH CENTRAL ARIZONA...NORTHEAST ARIZONA AND WEST CENTRAL ARIZONA. .DAY ONE...TODAY AND TONIGHT EXPECT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS NORTHERN ARIZONA TODAY. THE AIRMASS OVERHEAD IS QUITE UNSTABLE. THREATS TODAY ARE LOCALLY HEAVY RAIN AND SMALL HAIL. ACTIVITY SHOULD DECREASE BUT NOT END AFTER SUNSET. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY A VERY MOIST AND UNSTABLE AIRMASS WILL REMAIN FOR TUESDAY AND WEDNESDAY...WITH LOCALLY HEAVY PRECIPITATION FALLING. ON THURSDAY...SLIGHTLY DRIER AIR SHOULD BEGIN TO MAKE ITS WAY ACROSS NORTHERN ARIZONA...WITH LOWER CHANCES FOR PRECIPITATION THROUGH SUNDAY. $$
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1150 AM MST MON AUG 16 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1145 AM FLASH FLOOD 7 NE FLAGSTAFF 35.26N 111.53W
08/16/2010 COCONINO AZ TRAINED SPOTTER
LARGE DEBRIS FLOW THROUGH SIESTA WASH... AREA ROADS
IMPASSABLE.
&&
EVENT NUMBER FGZ1000175
COPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1157 AM MST MON AUG 16 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1155 AM FLASH FLOOD 7 NE FLAGSTAFF 35.26N 111.53W
08/16/2010 COCONINO AZ TRAINED SPOTTER
DEBRIS FLOW CROSSING PAINTBRUSH ROAD.
&&
EVENT NUMBER FGZ1000176
COThe Cedar City radar (KICX), 144 km away, was scanning. The volume nearest the first event began at 22:31 UTC.
1 flash flood. Local standard time, as filed.
A river gage on Havasu Creek showed a three foot rise.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2010Every state in 2010This day in weather historyWarnings in Arizona, August 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: 258518.