Thunderstorms moved northwest across southeast Arizona from late morning into early evening. Flash flooding occurred near Three Points and in Sabino and Bear Canyons where a large group of people became stranded.
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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.
Thunderstorms moved northwest across southeast Arizona from late morning into early evening. Flash flooding occurred near Three Points and in Sabino and Bear Canyons where a large group of people became stranded. A dust storm rolled across Interstate 10 in Pinal County.
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 12, 9:25 AM MST, 3 hours 25 minutes earlier.
Area Forecast Discussion National Weather Service Tucson AZ 925 AM MST Fri Aug 12 2022 .SYNOPSIS...A favorable pattern for daily thunderstorms will persist into next week, with daytime temperatures remaining near seasonable readings. && .DISCUSSION...This morning visible satellite shows midlevel clouds across the Southeast Arizona from the Catalina Mountains towards Sonora. The clouds are starting to clear out for the better cumulus clouds to form. There are left over bits from the complex west of Naco that can bring a light shower this morning along the International border. Otherwise, it is shaping up to a decent day for thunderstorms across the region. The 12Z sounding looks promising for thunderstorm development. The MUCAPE is 1383 J/KG; PWAT is 1.66 inches; modest CIN for the morning. We do have weak shear, so strong thunderstorms may not be likely to occur. The convective temperature is 94F and with the slight clearing of the midlevel clouds for the rest of the morning, the ground can get more substantial surface heating which will help break the cap. The forecasted high for Tucson is 99F and that seems to be on track. Only a handful of CAMs initialized well with the lingering complex along the International border and out towards Yuma. With that in mind, isolated to scattered thunderstorms can start to develop in the early afternoon and lasting into the evening. The better chances are along the higher terrain, such as the Mogollon Rim and the Sky Islands. If the last several days were any indication of storm evolution, like lasting up to 45 minutes in the lifecycle, we can get several rounds of storms starting in the afternoon, another in the evening, and another in the late night. WPC has the region under a slight risk for excessive rainfall and it checks out as the soil moisture in the eastern part of the CWA have been in the 98th percentile from the NASA SPORT. So, the chance of flash flooding is still here across the region and washes can get going pretty quick from a good raining storm. Most likely be isolated cases for flash flooding. The better chances for widespread flooding can occur next week, please see previous discussion. && .AVIATION...Valid through 13/12Z. Isolated SHRA/TSRA have already begun to develop early this morning primarily east of KTUS and KOLS but a brief VCSH can't be ruled out at either terminal. Coverage of SHRA/TSRA will increase after 12/19z remaining SCT throughout the afternoon before beginning a dissipating trend after 13/02z. With any storms at or near the terminals, strong wind gusts in excess of 40 kts, cloud heights dropping to 6k-8k ft, and vsby reductions will be possible for a brief time. Outside of storms, winds will remain around 10 kts or less. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...An active monsoon period is expected to continue into early next week, with daily rounds of scattered showers and thunderstorms. The typical threats of strong gusty winds and heavy rainfall remain, as well as the potential for precipitation outside the normal afternoon/evening cycles. Flash flooding will also remain a concern each day. Wind trends are otherwise light following a diurnal pattern. && .PREV DISCUSSION... /issued 244 AM MST Fri Aug 12 2022/ Isolated showers and even a couple lightning strikes can be seen across southeast Arizona early this morning. Based on the 12/00Z sounding, there is quite a bit of elevated instability to tap into to help generate these overnight storms. A complex over Sonora inched up toward the southern border of Cochise County, but cloud- tops are warming and this is now mostly anvil rain. The monsoon ridge is generally centered over eastern Colorado and it will gradually sag toward the southeast over the coming days. Mid and upper-level flow will weaken at times and become less directionally organized. Today we still have marginal cloud- layer winds from the south/southeast around 10 kts. Precipitable water is forecast to remain near to above normal for this time of year, and PoPs continue to be above climo. With saturated soils all the recent rains, the biggest threat to keep in mind is flash flooding, especially as storm motion weakens. WPC has our forecast area in a slight risk of excessive rainfall and this theme continues into the weekend. The most interesting feature on the horizon is the potential for an easterly wave that approaches toward the middle of next week. This can be seen on all ensemble guidance and will provide large- scale lift to an already moist environment. ECMWF EFI and the GEFS hint at the potential for anomalous rainfall amounts compared to climatology, but there's still plenty of time to see the evolution of how this pans out over the coming days. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Special Weather Statement
National Weather Service Tucson AZ
1041 AM MST Fri Aug 12 2022
AZZ504-506-507-514-121830-
Santa Catalina and Rincon Mountains including Mount
Lemmon/Summerhaven-Upper San Pedro River Valley including Sierra
Vista/Benson-Southeast Pinal County including
Kearny/Mammoth/Oracle-Tucson Metro Area including Tucson/Green
Valley/Marana/Vail-
1041 AM MST Fri Aug 12 2022
...A strong thunderstorm will impact portions of northeastern Pima
and southern Pinal Counties through 1130 AM MST...
At 1040 AM MST, Doppler radar was tracking a strong thunderstorm over
Mount Lemmon/Summerhaven, or 9 miles southeast of Catalina. This
storm was nearly stationary.
HAZARD...Winds in excess of 40 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Catalina, Mount Lemmon/Summerhaven and Seven Falls.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 3231 11077 3237 11086 3248 11088 3258 11082
3251 11067 3238 11061
TIME...MOT...LOC 1740Z 152DEG 2KT 3242 11076
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH
GLZThe Tucson radar (KEMX), 65 km away, was scanning. The volume nearest the first event began at 19:49 UTC.
2 flash flood, 1 dust storm. Local standard time, as filed.
Heavy rain of 1.5 in 1 hour caused flash flooding southeast of Three Points including Sierra Mountain Rd.
Heavy rain of 2-3 at the headwaters of Sabino Creek and Bear Canyon caused rapid rises in both streams. Flash flooding occurred at the Sabino Canyon Recreation area causing damage to trails and flooding of all recreation area bridges. Twenty five people became stranded in Bear Canyon and needed to be rescued as trails across the wash were flowing heavily and dangerously impassable. No injuries were reported.
A thunderstorm outflow boundary moved northwest along Interstate 10 lowering visibility to less than 1/4 mile from Picacho to Eloy.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2022Every state in 2022This day in weather historyWarnings in Arizona, August 2022
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: 1053808, 1053810, 1053814.