Abundant moisture and a mesoscale convective vortex from overnight storms in Sonora, Mexico were the focus for thunderstorm development. Some of the storms produced strong winds and heavy rainfall, including a microburst in Marana.
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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 TWC wrote it up.
Abundant moisture and a mesoscale convective vortex from overnight storms in Sonora, Mexico were the focus for thunderstorm development. Some of the storms produced strong winds and heavy rainfall, including a microburst in Marana.
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 Tucson, AZ wrote its last area forecast discussion before the first event at Aug 16, 2:10 PM MST, 2 hours earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 210 PM MST TUE AUG 16 2011 .SYNOPSIS...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO EARLY NEXT WEEK ALONG WITH SEASONABLE DAYTIME TEMPERATURES. && .DISCUSSION...WEAK MID-LEVEL LOW PRESSURE SYSTEM OVER NWRN SONORA WILL MOVE NWWD INTO FAR SWRN AZ TONIGHT...THEN SYSTEM IS PROGGED TO MOVE INTO SRN NEVADA BY THUR MORNING. AMPLE MOISTURE TO JUSTIFY SCATTERED SHOWERS/TSTMS ACROSS SE AZ THIS EVENING. THE BEST CHANCE OF PRECIP THIS EVENING SHOULD BE FROM TUCSON SWD-SWWD...AND FROM THE WHITE MOUNTAINS WWD INTO SE PINAL COUNTY. AFTER MIDNIGHT...CHANCE- CATEGORY POPS FOR WRN PIMA COUNTY...THE TOHONO OODHAM NATION...AND SOUTH-CENTRAL PINAL COUNTY. WILL MAINTAIN A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS ELSEWHERE. WED...AT THIS TIME APPEARS THAT SOME SUBSIDENCE WILL OCCUR BEHIND THE AFOREMENTIONED LOW PRESSURE SYSTEM. THUS WILL OPT FOR A SLIGHT CHANCE OF SHOWERS/TSTMS FROM TUCSON WWD...AND CHANCE-CATEGORY POPS ACROSS THE HIGHER TERRAIN EAST OF TUCSON. THUR-TUE...HIGH PRESSURE ALOFT PROGGED VIA THE 16/12Z GFS/ECMWF TO BE CENTERED OVER NEW MEXICO/WEST TEXAS. MEANWHILE...SHORTWAVE TROUGH TO APPROACH THE CALIFORNIA COAST THIS WEEKEND. AMPLE MOISTURE BETWEEN THE HIGH PRESSURE SYSTEM TO THE EAST AND THE TROUGH ALONG THE WEST COAST WILL MAINTAIN ISOLATED TO SCATTERED SHOWERS/TSTMS. DAYTIME TEMPS TO AVERAGE ABOUT 2-3 DEGS F OR SO OF NORMAL. && .AVIATION...EXPECT SCT TSRA/SHRA THRU 17/12Z THEN ISOLD-SCT TSRA/ SHRA WILL OCCUR WEDNESDAY. MVFR CIGS/VSBYS AND WIND GUSTS TO 45 KTS WITH STRONGER TSRA. OTHERWISE...SCT-BKN CLOUDS WITH BASES AT 6-10K FT AGL AND SURFACE WIND MAINLY LESS THAN 10 KTS THRU WEDNESDAY AFTERNOON. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...EXPECT ISOLATED TO SCATTERED THUNDERSTORMS INTO EARLY NEXT WEEK. NORMAL DIURNAL WIND TRENDS WILL OCCUR...EXCEPT STRONG AND GUSTY WINDS WILL PREVAIL NEAR THUNDERSTORMS. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. BF WEATHER.GOV/TUCSON
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TUCSON AZ 738 AM MST TUE AUG 16 2011 AZZ503-504-506>515-170600- UPPER SANTA CRUZ RIVER VALLEY/ALTAR VALLEY-TUCSON METRO AREA- SOUTHEAST PINAL COUNTY-UPPER SAN PEDRO RIVER VALLEY- EASTERN COCHISE COUNTY BELOW 5000 FEET-UPPER GILA RIVER VALLEY- WHITE MOUNTAINS OF GRAHAM AND GREENLEE COUNTIES- GALIURO AND PINALENO MOUNTAINS-CHIRICAHUA MOUNTAINS- DRAGOON AND MULE AND HUACHUCA AND SANTA RITA MOUNTAINS- CATALINA AND RINCON MOUNTAINS-BABOQUIVARI MOUNTAINS- 738 AM MST TUE AUG 16 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST ARIZONA. .DAY ONE...TODAY AND TONIGHT SCATTERED THUNDERSTORMS ARE EXPECTED THROUGH TONIGHT. THE MAIN THREATS WILL BE LOCALLY HEAVY RAINFALL AND WIND GUSTS OF 40 TO 50 MPH WITH THE STRONGER THUNDERSTORMS. PLEASE NOTE THAT EVEN MODERATE RAINFALL OVER THE RECENT BURN AREAS COULD RESULT IN FLASH FLOODING. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THERE WILL BE A CHANCE OF THUNDERSTORMS WEDNESDAY THROUGH MONDAY. THE MAIN THREATS WILL BE LOCALLY HEAVY RAIN AND GUSTY WINDS OVER 50 MPH. ALSO... EVEN MODERATE RAINFALL OVER THE RECENT BURN AREAS COULD RESULT IN FLASH FLOODING. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. AZZ501-502-505-170600- WESTERN PIMA COUNTY-TOHONO O'ODHAM NATION- SOUTH CENTRAL PINAL COUNTY- 738 AM MST TUE AUG 16 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST ARIZONA. .DAY ONE...TODAY AND TONIGHT SCATTERED THUNDERSTORMS ARE EXPECTED THROUGH TONIGHT. THE MAIN THREATS WILL BE LOCALLY HEAVY RAINFALL AND WIND GUSTS OF 40 TO 50 MPH WITH THE STRONGER THUNDERSTORMS. PLEASE NOTE THAT EVEN MODERATE RAINFALL OVER THE RECENT BURN AREAS COULD RESULT IN FLASH FLOODING. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THERE WILL BE A SLIGHT CHANCE OF MAINLY AFTERNOON AND EVENING THUNDERSTORMS WEDNESDAY THROUGH MONDAY. THE MAIN THREATS WILL BE LOCALLY HEAVY RAIN AND GUSTY WINDS OVER 50 MPH. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. WEATHER.GOV/TUCSON
The Tucson radar (KEMX), 64 km away, was scanning. The volume nearest the first event began at 23:08 UTC.
2 flash flood, 1 heavy rain, 1 thunderstorm wind. Local standard time, as filed.
Heavy rainfall resulted in zero visibility along Interstate 10 near Ina Road resulting in an accident. A tractor trailer drove into the median and flipped as a result on the heavy rainfall. The driver sustained minor injuries and was treated on scene.
Thunderstorms winds in Marana downed numerous trees from the Dove Mountain Community to Continental Reserve. A few trees were downed on homes with only minor damage sustained to roofs. The most significant damage occurred along Ina Road where 18 power poles were downed. Some poles fell on businesses and fences, and one fell on a moving commercial vehicle. Ina Road was closed for several hours, effectively isolating people in area businesses, parking lots and homes from the rest of the community.
Heavy rainfall amounts of 1 to 2 inches in less than 20 minutes resulted in widespread flash flooding near the Dove Mountain Community and Marana. Several streets were impassable for nearly an hour as water rushed through flooded washes and ditches. Notable road closures included Tangerine Road and Camino de Manana.
Heavy rainfall amounts of 1 to 2 inches resulted in flash flooding and several road closures across the Marana area. Flooding washes and ditches resulted in the closure of Cortaro Road from Thornydale Road to Interstate 10. Several additional neighborhood roads were flooded.
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, August 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: 344898, 341691, 341716, 341732.