Heavy rain from thunderstorms produced flash flooding and debris flows on the west side of community of White River in and below the Locust Fire area.
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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 FGZ wrote it up.
Heavy rain from thunderstorms produced flash flooding and debris flows on the west side of community of White River in and below the Locust Fire area.
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 Jul 20, 9:34 AM MST, 4 hours 26 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FLAGSTAFF AZ 934 AM MST WED JUL 20 2011 .SYNOPSIS...SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP TODAY OVER MOST AREAS...WITH A SLIGHT DRYING TREND NORTHWEST OF FLAGSTAFF. THIS DRYING TREND WILL CONTINUE THROUGH THURSDAY OR FRIDAY FROM FLAGSTAFF NORTH AND WEST...WHILE AREAS SOUTHEAST OF FLAGSTAFF WILL SEE LITTLE...IF ANY...DRYING TREND. BY THE WEEKEND...DEEP MOISTURE WILL MOVE BACK NORTHWARD INTO THE STATE WITH INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. && .DISCUSSION...CURRENT FORECAST LOOKS TO BE IN GOOD SHAPE WITH REGARDS TO PRECIP TRENDS AND EXPECTED WEATHER. ANOTHER DAY OF SCATTERED SHOWERS AND THUNDERSTORMS IS ANTICIPATED...ESPECIALLY FROM FLAGSTAFF EASTWARD. && .PREV DISCUSSION /345 AM MST/...DRIER AND SOMEWHAT WARMER AIR ALOFT WAS EVIDENT ON TUESDAY MOVING INTO NORTHWESTERN ARIZONA...AND WATER VAPOR IMAGERY IS STILL SHOWING THIS TREND. CONVECTIVE ACTIVITY YESTERDAY WAS MAINLY OVER THE CENTRAL AND EASTERN ZONES...AND THIS WILL CONTINUE TO BE THE CASE. MODELS DIFFER ON HOW MUCH DRYING WILL OCCUR...WITH THE ECMWF BEING THE MOST AGGRESSIVE...AND THE GFS BARELY TAKING THE TREND PAST THURSDAY. SPLITTING THE DIFFERENCE...WE WILL LIKELY HAVE LESS ACTIVITY FROM FLAGSTAFF NORTH AND WEST THROUGH ABOUT FRIDAY WHILE AREAS SOUTHEAST OF FLAGSTAFF WILL REMAIN IN MODERATE MONSOONAL CONDITIONS. BY THE WEEKEND...FLOW BECOMES SOUTHERLY ONCE AGAIN WITH POTENTIALLY DEEP MOISTURE MOVING BACK INTO THE STATE. && .AVIATION...FOR THE 18Z PACKAGE...SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP LATE THIS MORNING THROUGH THE AFTERNOON... MOST NUMEROUS SOUTHEAST OF A KPAN-KRQE LINE. EXPECT ERRATIC SURFACE WINDS WITH GUSTS 25-40 KTS AND MVFR/LOCAL IFR CONDITIONS NEAR THE HEAVIER SHOWERS AND STORMS. MOST CONVECTIVE ACTIVITY WILL DISSIPATE BY 03Z. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS. && PUBLIC..................KD/PETERSON AVIATION................JJ FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT WEATHER.GOV/FLAGSTAFF.
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE FLAGSTAFF AZ 500 AM MST WED JUL 20 2011 AZZ004>018-037>040-210700- WESTERN MOGOLLON RIM-GRAND CANYON COUNTRY-YAVAPAI COUNTY MOUNTAINS- YAVAPAI COUNTY VALLEYS AND BASINS-OAK CREEK AND SYCAMORE CANYONS- MARBLE AND GLEN CANYONS-KAIBAB PLATEAU-COCONINO PLATEAU- NORTHEAST PLATEAU AND MESAS HWY 264 NORTHWARD- NORTHEAST PLATEAU AND MESAS SOUTH OF HWY 264- CHINLE VALLEY-CHUSKA MOUNTAINS AND DEFIANCE PLATEAU- BLACK MESA AREA-LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTY- LITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTY- LITTLE COLORADO RIVER VALLEY IN APACHE COUNTY- EASTERN MOGOLLON RIM-WHITE MOUNTAINS-NORTHERN GILA COUNTY- 500 AM MST WED JUL 20 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR APACHE...COCONINO...NORTHERN GILA...NAVAJO...AND YAVAPAI COUNTIES IN NORTHERN ARIZONA. .DAY ONE...TODAY EXPECT SCATTERED SHOWERS AND THUNDERSTORMS BY LATE MORNING...MAINLY OVER AREAS SOUTHEAST OF FLAGSTAFF. STORMS WILL BE MORE ISOLATED NORTH AND WEST OF FLAGSTAFF AS DRIER AIR MOVES INTO THE REGION. THE MAIN THREAT WITH ANY THUNDERSTORMS TODAY WILL BE CLOUD-TO-GROUND LIGHTNING...MODERATE TO HEAVY RAIN...AND LOCALIZED HAIL. PERSONS IN FLASH FLOOD PRONE AREAS SHOULD PAY CLOSE ATTENTION TO THE WEATHER TODAY. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY DRIER AIR WILL CONTINUE TO AFFECT AREAS FROM FLAGSTAFF NORTH AND WEST THROUGH FRIDAY. PORTIONS OF THE STATE SOUTHEAST OF FLAGSTAFF AND NEAR THE NEW MEXICO BORDER WILL SEE LITTLE DRYING...AND STORM ACTIVITY WILL CONTINUE. BY THE WEEKEND...DEEP MOISTURE WILL RETURN WITH SHOWER AND THUNDERSTORM ACTIVITY INCREASING ACROSS THE REGION. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
156 PM MST WED JUL 20 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1214 PM DEBRIS FLOW 1 S ALPINE 33.83N 109.14W
07/20/2011 APACHE AZ DEPT OF HIGHWAYS
MUDSLIDE REPORTED JUST SOUTH OF US HWY 180 191
INTERSECTION
&&
EVENT NUMBER FGZ1100188
JJThe Flagstaff radar (KFSX), 138 km away, was scanning. The volume nearest the first event began at 21:01 UTC.
1 flash flood. Local standard time, as filed.
Heavy rain from a thunderstorm over the Locust Burn area produced significant debris flows and street flooding. Large rocks and sand were carried onto roadways and all drainages were full.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2011Every state in 2011This day in weather historyWarnings in Arizona, July 2011
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: 335763.