Monsoon storms knock out power across Phoenix as heat wave breaks

Powerful monsoon storms swept through the Phoenix area Sunday evening, August 9, 2026, knocking out power to more than 50,000 customers, downing trees and power lines, and bringing hail, dust and heavy rain. The storms arrived after Phoenix hit 111 degrees that afternoon, and forecasters say a cooling trend with continued storm chances will follow through the week.

What happened during Sunday night’s storms?

A line of severe thunderstorms moved into the Valley from the eastern mountains starting in the late afternoon. The National Weather Service issued a string of severe thunderstorm warnings covering Phoenix, Glendale, Peoria, Paradise Valley, Avondale, Goodyear, Buckeye, Arlington and Wintersburg, with one warning noting wind gusts up to 70 mph near Buckeye. A flash flood warning also covered Avondale, Goodyear and Buckeye until 1 a.m. Hail was reported at North Mountain Park in Phoenix, and a large wall of dust triggered a Dust Storm Warning as it pushed north out of Pinal and southern Maricopa County, eventually reaching the Phoenix metro. According to the Maricopa County Flood Control District, the North Phoenix area near North Mountain Park recorded 0.47 inches of rain by 10:25 p.m.

How many people lost power?

Outages climbed steadily through the evening. ABC15’s live tracking showed roughly 12,000 SRP customers without power early on, climbing past 31,000 and then above 40,500 combined SRP and APS customers by around 9:45 p.m., with outages concentrated near the old MetroCenter mall site and across the West Valley. AZFamily reported that by 10:30 p.m., about 52,000 SRP and APS customers combined were in the dark, mostly in the West Valley. Specific damage included a large pole down near 7th Street and Dunlap Avenue and a tree that fell on a power line at 51st Avenue and Thomas Road, with additional lines reported down near 51st and Glendale avenues.

What’s driving the region’s dust problem?

FOX 10 reported that dust has lingered over Phoenix following storms on Aug. 3 and Aug. 6, both of which Arizona State University classified as “Category 5” events under a new public dust-severity scale — the first year ASU has released this data. Ryan Heintzman of ASU’s School of Geographical Sciences and Urban Planning said the scale, unlike the National Weather Service’s visibility-based measure, weighs wind speed, storm duration and particulate matter. Phoenix NWS meteorologist Alicia Ryan said the Aug. 6 dust blew in without enough follow-on wind to clear it, so it settled and stayed over the metro area. Emergency physician Frank LoVecchio warned that fine particulates can penetrate deep into lungs, triggering coughing and wheezing and turning a routine day into an ER visit for people with severe asthma or COPD; wind-borne fungal spores can also cause Valley Fever, with symptoms resembling pneumonia. Rain expected Aug. 10 and Aug. 13 was seen as a potential way to finally clear the lingering dust.

How much cooler will it get?

Monday’s high was expected around 108 degrees with a 30% chance of storms overnight into early Tuesday. Tuesday was forecast to cool further to about 104 degrees, with a 20% storm chance into Wednesday morning. Wednesday’s high was projected at just 101 degrees with another 30% storm chance that evening, and Thursday could top out around 100 degrees with only a slight chance of storms. Friday looked comparatively mild for Phoenix at about 103 degrees, before temperatures climb back to 106–108 degrees over the following weekend. A Flood Watch was in effect Monday afternoon through evening for southern Arizona, including Tucson, and northern and eastern Arizona’s high country was expected to see widespread storm activity from Monday through Thursday.

Why does this matter for the Valley?

The storms mark a shift in Phoenix’s monsoon pattern after an extended stretch of extreme heat — Sunday’s Extreme Heat Warning expired at 8 p.m. the same night storms rolled in. The combination of heat, wind-driven dust and heavy rain creates compounding hazards: power outages during hot weather, flash flooding in low-lying desert washes, and prolonged poor air quality that disproportionately affects older adults, children and people with respiratory conditions. ASU’s new dust classification system gives officials and the public a more detailed way to track these events going forward.

How does coverage differ across outlets?

AZFamily and ABC15 focused on real-time storm tracking — outages, warnings and rainfall totals — while FOX 10 devoted separate coverage to the health and air-quality fallout from the dust that preceded the storms. 12 News and one FOX 10 video segment offered only brief broadcast-style updates without additional written detail.

Sources

• AZFamily — Temperatures cool as monsoon moisture increases · Monsoon storms hit Phoenix area with rain, strong winds · Phoenix heat wave ends mid-week as monsoon storms usher in cooler temperatures
• ABC15 Arizona — RAINFALL TOTALS: How much rain has fallen around the Valley? 8-9-26 · LIVE UPDATES: Monsoon storms moving through the Valley Sunday night
• 12 News Phoenix
• FOX 10 Phoenix — Dust causing health concerns as more monsoon storms approach · Severe thunderstorms moving through Phoenix metro area · Phoenix dust storms prompt health warnings as Category 5 dust lingers · Highs reach 111 degrees with monsoon rain and dust risks · Lack of rain leads to longer-lasting dust

Featured photo: DPPed via Wikimedia Commons (CC BY-SA 3.0)