A shortwave trough moving through the region combined with a moist, unstable atmosphere promoted the development of showers and thunderstorms across south-central Arizona going into the afternoon on the 18th. Adequate shear allowed for some thunderstorms to become strong to severe, leading to multiple reports of damaging winds and dense blowing dust. Additionally, thunderstorms were capable of producing locally heavy rainfall leading to isolated flash flooding. No injuries were reported.

Dust Storm in NORTHWEST PINAL COUNTY, ARIZONA
From 18-SEP-21 21:50:00 to 18-SEP-21 22:30:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Strong outflow winds led to dense blowing dust in Maricopa that resulted in visibility being reduced below a quarter mile near Murphy Road and Farrell Road. Additionally, an Arizona Department of Transportation traffic camera along I-10 at Sacaton showed estimated visibility below a quarter mile. No accidents or injuries were reported.

Dust Storm in SOUTHEAST VALLEY/QUEEN CREEK, ARIZONA
From 18-SEP-21 22:40:00 to 18-SEP-21 22:50:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Video on social media showed visibility estimated under 100 yards near Val Vista Drive and Appleby Road. Further east, near zero visibility was reported at the Olive Mill Garlic Fest in Queen creek due to dense blowing dust. No accidents or injuries were reported.

Dust Storm in EAST VALLEY, ARIZONA
From 18-SEP-21 23:45:00 to 18-SEP-21 23:55:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Video from social media showed dense blowing dust along the 202 freeway near Williams Field Road causing estimated visibility to be reduced to around 50-100 yards. No accidents or injuries were reported.

Thunderstorm Wind in PINAL, ARIZONA
From 18-SEP-21 14:50:00 to 18-SEP-21 14:50:00 (MST-7)
Location: LIRIM
Magnitude: 50.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Multiple photos on social media showed numerous power poles were knocked over west of Maricopa along Ralston Road between Highway 238 and McDavid Road. No injuries were reported.

Thunderstorm Wind in MARICOPA, ARIZONA
From 18-SEP-21 15:38:00 to 18-SEP-21 15:38:00 (MST-7)
Location: HELENA
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A tree was reported down on McClintock Drive between Elliot Road and Warner Road blocking southbound traffic. No injuries were reported.

Thunderstorm Wind in MARICOPA, ARIZONA
From 18-SEP-21 15:40:00 to 18-SEP-21 15:40:00 (MST-7)
Location: MC QUEEN
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Utility Company

According to the Salt River Project (SRP), a power pole was blown over near Main Street and Dobson Road. No injuries were reported.

Flash Flood in MARICOPA, ARIZONA
From 18-SEP-21 16:03:00 to 18-SEP-21 16:23:00 (MST-7)
Location: MOBILE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Video on social media showed part of Highway 238 appearing to be impassable between mile posts 33-35 due to flooding. The Arizona Department of Public Safety (DPS) also responded to a vehicle stalled due to flooding in this area. No injuries were reported.