As the region transitioned out of the monsoon, a compact low created a high shear - modest CAPE environment. Parameters were sufficient for supercell development and a few supercells did develop amongst isolated to scattered storms in the afternoon across South-central Arizona, including a right-mover that pushed into Phoenix and a left split. The environment was supportive of severe to large hail with lower freezing levels and steep mid-level lapse rates. Measured hail stones up to 1.0 to 1.5 diameter was observed with the few supercells. Most other storms also produced smaller hail throughout the day. Damaging winds and isolated flash flooding was also observed through the afternoon.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 18:12:00 to 05-OCT-21 18:12:00 (MST-7)
Location: (PHX)SKY HARBOR ARPT
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Social media photo of estimated nickel-sized hail.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 18:42:00 to 05-OCT-21 18:42:00 (MST-7)
Location: SCOTTSDALE MUNI
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Social media video of estimated penny-sized hail falling.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 18:42:00 to 05-OCT-21 18:42:00 (MST-7)
Location: SCOTTSDALE MUNI
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Social media video of estimated penny-sized hail.

Thunderstorm Wind in PINAL, ARIZONA
From 05-OCT-21 13:37:00 to 05-OCT-21 13:37:00 (MST-7)
Location: PALM SPGS
Magnitude: 52.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Salt River Project EM reported 3 wooden power poles were broken near the Spurlock substation, causing power outages. Wind speeds estimated around 60 mph. Time estimated from radar. No injuries were reported. Full extent of damage not provided.

Thunderstorm Wind in MARICOPA, ARIZONA
From 05-OCT-21 14:05:00 to 05-OCT-21 14:05:00 (MST-7)
Location: TORTILLA FLAT
Magnitude: 63.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Mesonet station SRP45 measured a 73 mph wind gust.

Thunderstorm Wind in GILA, ARIZONA
From 05-OCT-21 14:28:00 to 05-OCT-21 14:28:00 (MST-7)
Location: ROOSEVELT
Magnitude: 55.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Mesonet station AU919 (2 SSE Roosevelt) measured a 63 mph wind gust.

Flash Flood in MARICOPA, ARIZONA
From 05-OCT-21 14:10:00 to 05-OCT-21 15:10:00 (MST-7)
Location: TORTILLA FLAT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Social media video showed swift-moving water within Weekes Wash and flowing across State Route 88 near 1st Water Road, making the road impassable. Timing approximated. No damages or injuries were reported.

Flash Flood in GILA, ARIZONA
From 05-OCT-21 15:04:00 to 05-OCT-21 16:00:00 (MST-7)
Location: PUNKIN CENTER
Flood cause: Heavy Rain / Burn Area
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Arizona Department of Transportation reported State Route 188 was closed between mile post 251 and 255 due to a mudslide. Photos show 4 to 6 feet of mud across the highway near mile post 253 that had to be cleared with heavy machinery. Flow originated from a portion of the 2020 Bush fire burn scar. NWS Phoenix in collaboration with Arizona Geological Survey declared the mudslide a hyperconcentrated flow and therefore entered as a flash flood. Timing estimated from radar. No damage or injuries were reported.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 12:00:00 to 05-OCT-21 12:00:00 (MST-7)
Location: BUCKHORN
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Images on social media showed accumulating hail with the larges stones estimated up to nickel size.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 16:13:00 to 05-OCT-21 16:13:00 (MST-7)
Location: (GBN)GILA BEND MUNI
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Observer at Gila Bend Airfield reported 1 inch diameter hail in the METAR.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 17:13:00 to 05-OCT-21 17:13:00 (MST-7)
Location: LIBERTY
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Chaser estimated golf ball sized hail fell near Riggs Road and Bullard Avenue in Rainbow Valley. No damages reported. Time estimated from radar.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 17:46:00 to 05-OCT-21 17:46:00 (MST-7)
Location: GILA CROSSING
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Storm chaser reported estimated 1 inch diameter hail while driving on Loop-202.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 17:58:00 to 05-OCT-21 17:58:00 (MST-7)
Location: LAVEEN
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail just less than 1 inch in diameter fell for roughly 10 minutes based on a social media report.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 18:02:00 to 05-OCT-21 18:02:00 (MST-7)
Location: (PHX)SKY HARBOR ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Social media photo of a 1 inch diameter hail stone.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 18:04:00 to 05-OCT-21 18:04:00 (MST-7)
Location: (PHX)SKY HARBOR ARPT
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Social media photo of an estimated 1.5 inch in diameter hail stone. Hail reportedly fell for around 5 minutes.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 18:04:00 to 05-OCT-21 18:04:00 (MST-7)
Location: (PHX)SKY HARBOR ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Social media video showing a collection of hail with the largest stones estimated around 1 inch in diameter.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 18:05:00 to 05-OCT-21 18:05:00 (MST-7)
Location: (PHX)SKY HARBOR ARPT
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Social media photo of hail stones estimated up to 1.25 inches in diameter.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 18:06:00 to 05-OCT-21 18:06:00 (MST-7)
Location: (PHX)SKY HARBOR ARPT
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Multiple videos from Phoenix Sky Harbor Airport showing hail falling with sizes estimated around pea to penny.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 18:03:00 to 05-OCT-21 18:03:00 (MST-7)
Location: (PHX)SKY HARBOR ARPT
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Social media video shows hail falling in Hermoso Park. Largest stones estimated at 1.25 inches in diameter.

Hail in MARICOPA, ARIZONA
From 05-OCT-21 12:00:00 to 05-OCT-21 12:00:00 (MST-7)
Location: VELDA ROSE ESTATES
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Social media photos show hail stones up to nickel-sized. Time estimated from radar.