Thunderstorms with heavy rain in the Cataract/Havasu Creek drainage during the evening of August 2nd caused flooding problems in the Village of Supai and the Havasupai Campground.
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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.
Thunderstorms with heavy rain in the Cataract/Havasu Creek drainage during the evening of August 2nd caused flooding problems in the Village of Supai and the Havasupai Campground.
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 1, 2:30 AM MST, 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FLAGSTAFF AZ 230 AM MST WED AUG 1 2012 .SYNOPSIS...A WEAK UPPER LEVEL DISTURBANCE WILL LINGER OVER MOHAVE COUNTY AND THE HIGH PRESSURE RIDGE WILL SHIFT SOUTH INTO NORTHERN MEXICO. EXPECT GOOD CHANCES FOR HEAVY SHOWERS AND THUNDERSTORMS TO CONTINUE TODAY. HOWEVER THE SHIFT IN THE RIDGE WILL BRING IN DRIER AIR FROM THE SOUTHWEST REDUCING OUR STORM COVERAGE ON THURSDAY AND FRIDAY. GOOD CHANCES FOR STORMS WILL RETURN ON SATURDAY AND SUNDAY AS ANOTHER UPPER LEVEL DISTURBANCE MOVES THROUGH WESTERN ARIZONA. && .DISCUSSION...AN UPPER LEVEL LOW OVER MOHAVE COUNTY WILL CONTINUE TO LINGER AS THE HIGH PRESSURE RIDGE OVER THE FOUR CORNERS SHIFTS SOUTH INTO NORTHERN MEXICO TODAY. THIS PATTERN SHIFT WILL CAUSE THE UPPER LEVEL WIND FLOW TO SHIFT FROM MOIST SOUTHEASTERLIES TO DRIER SOUTHWESTERLIES THROUGH THE DAY. ENOUGH MOISTURE AND AIR MASS INSTABILITY WILL BE PRESENT FOR ONE MORE GOOD DAY OF HEAVY SHOWER AND THUNDERSTORM ACTIVITY. HOWEVER BY THURSDAY MOISTURE LEVELS WILL DRY OUT A BIT AND STORM COVERAGE WILL BE REDUCED THROUGH FRIDAY. SATURDAY AND SUNDAY...MODELS SHOW ANOTHER UPPER LEVEL LOW MOVING ACROSS THE ARIZONA CALIFORNIA BORDER BY EARLY SATURDAY MORNING. THIS LOW MOVEMENT WILL LIKELY CAUSE THE HIGH PRESSURE RIDGE TO SHIFT BACK NORTH TO THE FOUR CORNERS...CHANGING OUR DRIER SOUTHWESTERLY WINDS BACK TO A MORE MOIST SOUTHEASTERLY WIND FLOW. THE COMBINATION OF ADDITIONAL MOISTURE AND DYNAMICS ASSOCIATED WITH THE UPPER LEVEL LOW WILL BRING US BACK INTO A WET MONSOON PATTERN JUST IN TIME FOR THE WEEKEND. NEXT WEEK...LONG RANGE MODEL PROJECTIONS ARE HINTING AT A MAJOR SHIFT IN THE HIGH PRESSURE PATTERN NEXT WEEK...PLACING THE CENTER OF THE MID LEVEL HIGH DIRECTLY OVER NORTHERN ARIZONA. IF THIS PATTERN CHANGE CONTINUES TO PLAY OUT AS THE MODELS SUGGEST...THEN WE WILL SEE A SIGNIFICANT DRYING PERIOD NEXT WEEK WITH LESS STORM ACTIVITY. && .AVIATION...FOR THE 12Z PACKAGE...SCT SHRA/TSRA DEVELOPING AFT 17-19Z. THE STRONGEST STORMS MAY PRODUCE MVFR/IFR CONDITIONS. ACTIVITY DIMINISHING AFT 03-05Z. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && PUBLIC.........BOHLIN AVIATION.......DB FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT WEATHER.GOV/FLAGSTAFF
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE FLAGSTAFF AZ 303 PM MST TUE JUL 31 2012 AZZ004>018-037>040-010700- 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- 303 PM MST TUE JUL 31 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL ARIZONA...NORTH CENTRAL ARIZONA...NORTHEAST ARIZONA AND WEST CENTRAL ARIZONA. .DAY ONE...THIS AFTERNOON AND TONIGHT A MOIST AND UNSTABLE AIR MASS WILL CONTINUE TO BRING MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS TO NORTHERN ARIZONA THROUGH THIS EVENING. SOME OF THESE STORMS MAY PRODUCE SUBSTANTIAL RAINFALL IN A SHORT PERIOD OF TIME RESULTING IN LOCALIZED FLOODING. LARGE HAIL AND STRONG WINDS ARE ALSO POSSIBLE IN THE STRONGEST STORMS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY SHOWERS AND THUNDERSTORMS WILL CONTINUE EACH DAY BUT THE RISK OF HEAVY RAINFALL WILL DECREASE DURING THE LATTER HALF OF THE WEEK. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
The Cedar City radar (KICX), 153 km away, was scanning. The volume nearest the first event began at 10:01 UTC.
1 flash flood. Local standard time, as filed.
Flood waters from heavy rain that fell on Tuesday evening (July 31) reached Supai Village between 230 and 300 AM. Water up to several feet caused trails and bridges to become impassible. This stranded several hikers and flooded area campgrounds.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2012Every state in 2012This day in weather historyWarnings in Arizona, August 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: 410852.