A number of rounds of thunderstorms were triggered by a westward moving upper level weather system across southeast Arizona from the afternoon of July 22 into the early morning of July 23. Thunderstorms produced wind damage and flash flooding in Douglas, Green Valley and the Tucson Metro area.
Every event with a place to put it. Tap one for its entry below.
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.
A number of rounds of thunderstorms were triggered by a westward moving upper level weather system across southeast Arizona from the afternoon of July 22 into the early morning of July 23. Thunderstorms produced wind damage and flash flooding in Douglas, Green Valley and the Tucson Metro area. Flooding also occurred along the San Pedro River as well as the Pantano Wash and Rillito River, and eventually downstream along the Santa Cruz River. In Graham County, 1 fatality occurred in a flash flood of the Cottonwood Wash near Pima on July 22.
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 Jul 22, 2:45 PM MST, 1 hour 35 minutes earlier.
Area Forecast Discussion National Weather Service Tucson AZ 245 PM MST Thu Jul 22 2021 .SYNOPSIS...An approaching weather system from the east will bring widespread showers and thunderstorms to the area tonight through Saturday night. Locally heavy rainfall combined with a saturated ground from recent rains may result in flash flooding and flooding during this period. Improving weather can be anticipated late Sunday, although elevated flows in area washes and streams will still be possible. Thereafter, a decrease in daily shower and thunderstorm activity can be expected early next week. High temperatures will be below normal for the next week with well below normal highs Friday through Sunday. && .DISCUSSION...Convection going on as expected this afternoon S/SW of Tucson and NE of Tucson up to the White mountains. Storms will be moving to the W/SW with portions of the area under marginal risk for severe thunderstorms. Blowing dust will be issue into the evening hours. CAMs still indicating that a rim shot later this evening moving SW into the lower deserts. This will be the beginning of a multi- day heavy rain/flash flooding/flood event for the area with the soils already saturated. A flash flood watch for the entire area goes into effect at 6 pm this evening and runs through at least Saturday night. This may end up being extended by future shifts. The culprit for this heavy rain/flash flooding/flooding event is an anomalous upper level low, currently near the Texas Big Bend this afternoon, which will be retrograding west across Arizona over the next 72 hours. Thus the forecast area will see periods of moderate to heavy rain over the next three days as the dynamics from this upper low rotate across the area. Latest 72 hr rainfall totals for the area from WPC, except for wrn Pima County, has 1"-3" in the valleys and 3"-8" in the mountains. What is interesting about this event is that once the upper low is west of Tucson, likely Saturday evening, there will be a period of 10-20 kt upslope flow into the south facing portions of the Catalina mountains and the Bighorn burn scar, which may enhance rainfall rates in that time period. Next week: We're back into a normal monsoon pattern with a chance of afternoon and evening showers and thunderstorms. High temperatures will be heating back up but remaining below normal. && .AVIATION...Valid through 24/00Z. SCT-BKN clouds at 8k-12k ft MSL much of the period. Scattered to numerous SHRA/TSRA developing this afternoon and remain into the nighttime period. Precipitation is expected to continue to develop tomorrow as an active period of weather persists. Expect brief MVFR CIGS/VSBYS and mountain obscurations around TSRA along with gusty outflow winds, potentially in excess of 45 kts with the strongest storms. Otherwise, SFC wind generally less than 12 kts following diurnal trends. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Periods of heavy rainfall are expected today into the weekend, with scattered to numerous showers and thunderstorms. Flooding issues are anticipated due to soils already being fairly saturated from an active start to the monsoon. While in this pattern, showers and storms will be possible at all hours of the day and overnight. Gusty winds in excess of 40 mph and numerous lightning strikes may accompany stronger storms. Daytime temperatures will remain below normal. 20-foot winds will generally be less than 15 mph when not influenced by thunderstorms. && .HYDROLOGY...Given the chance for heavy rainfall and already saturated soils the potential for flows in rivers and washes is high. The latest river forecasts from the Colorado Basin River Forecast Center show Sabino Creek, Pantano Wash near Vail, and Santa Cruz River at Trico Road rising near or to flood stage on Saturday. However, most river forecasts across southeast Arizona show elevated stream flow over the weekend. With high enough rainfall amounts other locations could reach flood stage and possibly out of bank flow. Stream flow may also take longer to recede if basin receives multiple days of rainfall. Potentially leading to elevated stream flow into early next week. River observations and forecasts can be found at the following sites: https://water.weather.gov/ahps2/index.php?wfo=twc http://www.cbrfc.noaa.gov && .CLIMATE...Daily rainfall records are likely to be broken across southeast Arizona through Saturday. Interesting high temperature note. There is a 13% chance that the high temperature in Tucson on Saturday may may not get out of the 70s. Since 1895, there have only been 10 days in July in which the high temperature was in the 70s with the last occurrence being July 22, 1998 when the high was 76. Interesting. && .TWC WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch from 6 PM MST this evening through Saturday evening for AZZ501>515. && Public and Climate...74 Aviation and Fire Weather...Howlett Hydrology...Boyle Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Special Weather Statement National Weather Service Tucson AZ 104 PM MST Thu Jul 22 2021 AZZ503-507-513-222030- Upper San Pedro River Valley including Sierra Vista/Benson-Dragoon/Mule/Huachuca and Santa Rita Mountains including Bisbee/Canelo Hills/Madera Canyon-Upper Santa Cruz River and Altar Valleys including Nogales- 104 PM MST Thu Jul 22 2021 ...SIGNIFICANT WEATHER ADVISORY FOR EASTERN SANTA CRUZ COUNTY UNTIL 130 PM MST... At 104 PM MST, Doppler radar was tracking a strong thunderstorm 9 miles southeast of Patagonia, or 21 miles northeast of Nogales, moving west at 10 mph. Winds in excess of 40 mph will be possible with this storm. Locations impacted include... Nogales, Patagonia, Sonoita, Elgin, Nogales International Airport, Patagonia Lake State Park, Kino Springs, Canelo, Lochiel and Madera Canyon. LAT...LON 3172 11091 3169 11049 3133 11048 3133 11091 TIME...MOT...LOC 2004Z 090DEG 9KT 3148 11061 RH
Special Weather Statement National Weather Service Tucson AZ 234 PM MST Thu Jul 22 2021 AZZ503-504-507-513-222200- Upper San Pedro River Valley including Sierra Vista/Benson-Dragoon/Mule/Huachuca and Santa Rita Mountains including Bisbee/Canelo Hills/Madera Canyon-Upper Santa Cruz River and Altar Valleys including Nogales-Tucson Metro Area including Tucson/Green Valley/Marana/Vail- 234 PM MST Thu Jul 22 2021 ...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL PIMA AND NORTH CENTRAL SANTA CRUZ COUNTIES UNTIL 300 PM MST... At 234 PM MST, Doppler radar was tracking a strong thunderstorm 7 miles north of Sonoita, or 19 miles southeast of Sahuarita, moving west at 10 mph. Winds in excess of 40 mph will be possible with this storm. Locations impacted include... East Sahuarita, Sonoita and Madera Canyon. LAT...LON 3189 11057 3168 11057 3162 11092 3195 11088 TIME...MOT...LOC 2134Z 100DEG 9KT 3179 11069 RH
The Tucson radar (KEMX), 45 km away, was scanning. The volume nearest the first event began at 23:19 UTC.
7 flash flood, 5 thunderstorm wind, 2 flood, 1 hail. Local standard time, as filed.
Thunderstorm winds downed a tree near the intersection of Speedway and Craycroft, which led to a traffic accident.
One to two inches of rain in less than 1 hour over east central Tucson caused flash flooding along and near Alamo Wash. A child was rescued from flood waters near 22nd and Kolb. Farther north, Alamo Wash overtopped Speedway Blvd and Sahuara Ave.
Thunderstorm winds downed a power pole and caused minor damage to a house in Chuichu.
Thunderstorm winds downed several trees and blew a metal roof off a hardware store in Douglas.
Heavy rain of 1.5 to 2.5 fell in less than 1 hour in the Douglas area causing flash flooding of streets and caused the closure of Washington Ave where several homes were flooded and a block wall was knocked down by flood waters. West of town, Kings Highway just north of State Route 80 was closed due to flooding.
Heavy rain of 2 to 2.5 fell in less than 2 hours between the Pinaleno Mountains and Highway 70 west of Safford. This caused flash flooding of roads in the Pima area and significant rises in Cottonwood Wash. A large SUV which was attempting to cross the wash and carrying two adults and four children was swept away in the floodwaters. A four-year old girl drown during the rescue attempt. Her body was found four days later downstream in the Gila River near Eden.
Thunderstorm winds downed 60 power poles and numerous trees and in Green Valley and Sahuarita, mostly along La Canada Dr. from Duval Mine Rd to near Anamax Rd. and near the entrance to Quail Creek. A traffic signal was also damaged in Green Valley while the wall of a townhouse was blown over in Sahuarita.
Heavy rain of 1 to 1.5 fell in less than 1 hour along the entire length of the San Pedro River from San Manuel to Dudleyville and 3 fell near Dudleyville caused the river to rise rapidly, with a greater than 7 foot rise measured in one hour near Mammoth. Extensive flash flooding and severe damage to nearby roadways occurred in the San Manuel, Mammoth and Dudleyville areas.
A large area of 1 to 2 of rain fell in less than 90 minutes in southeast Pima County and caused extensive flash flooding from southeast Tucson and Vail southwest to Sahuarita and Green Valley. In the Vail area, three to four feet of water washed out East Andrada Rd at the Santa Rita Wash and a car was swept downstream 300 yards, but the occupants escaped unharmed. Many roads in Saguaro National Park East were also flooded or closed. In southeast Tucson, a person was rescued from a sandbar in the Pantano Wash near Harrison Rd. and farther south, Sahuarita and Wilmot Rds. were closed. In Sahuarita a woman was rescued from her vehicle at Beta Street and the Interstate 19 Frontage Rd. In Green Valley, several roads were closed and homes were flooded in the Casa de Abrego neighborhood east of I-19.
Thunderstorm winds downed a tree near Interstate 10 and Houghton.
A large area of 1 to 3 of rain fell in less than 1 hour over much of the Tucson Metro Area, including parts of the Bighorn burn scar. Around ten swift water rescues were performed during the overnight hours for motorists trapped in vehicles including near Escalante and Sarnoff. Plus, two people were rescued from the Rillito River near La Canada Dr. Also, many trails were damaged at Sabino Canyon Recreation Area and six homes were flooded in near Finger Rock Wash in the Catalina Foothills due to runoff from the Bighorn burn scar. No injuries were reported.
A broad area of 1 to 2 of rain fell in less than 1 hour from the Tucson Mountains west to Picture Rocks. Numerous streets were flooded, closed and/or damaged as a result. At least one vehicle was stranded in flood waters, on Manville Rd.
Widespread heavy rain across eastern Pima County resulted in widespread flooding of roadways and high flows along Pantano Wash and Rillito River. Significant damage to the Loop hiking and biking trail system occurred.
Heavy rains upstream in the basin late July 22 into July 23, raised water levels in the Santa Cruz River and Greene Wash in Pinal County. Several roads were washed out where the Santa Cruz becomes multi-channeled from west of Pinal Airpark to southwest of Picacho.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Flash Flood, Graham | 2021-07-22 | 4 | Female | Vehicle/Towed Trailer | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2021Every state in 2021This day in weather historyWarnings in Arizona, July 2021
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: 976224, 976225, 976231, 976226, 976227, 976332, 976232, 976228, 976349, 976342, 976229, 976353, 976357, 976358, 976374.