Thunderstorms produced heavy rain in the Paria River Basin in Utah. The water flowed southeast into Arizona and caused flash flooding in the Paria River.
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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 produced heavy rain in the Paria River Basin in Utah. The water flowed southeast into Arizona and caused flash flooding in the Paria River.
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 19, 8:30 PM MST, 4 hours 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FLAGSTAFF AZ 830 PM MST SUN AUG 19 2012 .SYNOPSIS...A MOIST AND UNSTABLE AIR MASS WILL REMAIN OVER ARIZONA FOR THE NEXT SEVERAL DAYS BRINGING DAILY SHOWERS AND THUNDERSTORMS TO THE REGION. && .DISCUSSION...CONVECTIVE ACTIVITY IS SLOWLY WINDING DOWN ACROSS NRN AZ THIS EVENING...WITH JUST A FEW AREAS OF LIGHT SHOWERS LINGERING. EXPECT MOST ACTIVITY TO END LATER THIS EVENING. && .PREV DISCUSSION (325 PM)...UNSETTLED WEATHER WILL PERSIST ACROSS THE REGION FOR THE NEXT SEVERAL DAYS...WITH SCATTERED THUNDERSTORMS EXPECTED EACH AFTERNOON AND EVENING. GFS AND ECMWF BOTH INDICATE DRYING CONDITIONS BY THE COMING WEEKEND AS HIGH PRESSURE SETS UP TO OUR SOUTHWEST...BUT WE WILL CONTINUE WITH AT LEAST SLIGHT CHANCES FOR PRECIP IN THE FORECAST AT THIS TIME. OTHERWISE...MODERATE MONSOON CONDITIONS...GENERALLY LIGHT WINDS...AND NEAR NORMAL TEMPERATURES ARE LIKELY TO PERSIST. && .AVIATION...FOR THE 06Z PACKAGE...ISOLD -SHRA WILL CONTINUE TO DIMINISH OVERNIGHT. AFT 16-18Z...SCT-NMRS SHRA/TSRA WILL REDEVELOP WITH MVFR/IFR CONDITIONS PSBL IN THE STRONGER STORMS. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && PUBLIC.........DB/KD AVIATION.......DB FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT WEATHER.GOV/FLAGSTAFF
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE FLAGSTAFF AZ 700 PM MST SUN AUG 19 2012 AZZ004>018-037>040-200700- 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- 700 PM MST SUN AUG 19 2012 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 DEEP MOISTURE COVERS NEARLY ALL OF NORTHERN ARIZONA...EXCEPT THE FOUR CORNERS REGION. EXPECT SCATTERED THUNDERSTORMS TO DEVELOP THIS AFTERNOON AND CONTINUE INTO THE EVENING HOURS. THE PRIMARY THREATS ARE FREQUENT LIGHTNING...HEAVY RAIN...AND STRONG GUSTY WINDS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY A MOIST AND UNSTABLE AIR MASS WILL REMAIN ACROSS ARIZONA FOR THE NEXT SEVERAL DAYS. EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP EACH DAY. PRIMARY THREATS WILL CONTINUE TO BE HEAVY RAIN AND FREQUENT LIGHTNING. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
The Cedar City radar (KICX), 110 km away, was scanning. The volume nearest the first event began at 08:00 UTC.
1 flash flood. Local standard time, as filed.
A river gage in Paria Canyon measured a four foot rise in less than 30 minutes on the Paria River.
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: 410855.