Deep monsoon moisture over Arizona and an approaching trough of low pressure from the Pacific Northwest helped produce local flash flooding and large hail. Thunderstorms reformed during the evening over Yavapai County which continued flash flooding in smaller streams and rapid rises on The Verde River (a main stem river).

Flash Flood in COCONINO, ARIZONA
From 18-AUG-21 04:00:00 to 18-AUG-21 09:00:00 (MST-7)
Location: MARBLE CANYON
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Paria River gauge at Lees Ferry showed a 4 foot rise between 6:00 AM and 7:00 AM MST. The Paria River drainage originates in Utah and flows into the Colorado River near Lees Ferry.

Flash Flood in GILA, ARIZONA
From 18-AUG-21 08:00:00 to 18-AUG-21 11:00:00 (MST-7)
Location: STRAWBERRY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The East Verde River near Childs (EVDA3) had a 2.9 foot rise between 0800 and 0845 MST.

Flash Flood in GILA, ARIZONA
From 18-AUG-21 08:45:00 to 18-AUG-21 10:30:00 (MST-7)
Location: JAKES CORNER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Tonto Creek stream gauge above Gun Creek (TNRA3) measured a 3.1 foot rise between 0845 and 1000 AM MST.

Flash Flood in COCONINO, ARIZONA
From 18-AUG-21 12:29:00 to 18-AUG-21 14:30:00 (MST-7)
Location: MUNDS PARK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: County Official

The water was flowing 4.85 feet deep (normally dry) in Munds Canyon under Interstate 17 and about 25 feet wide. The estimated flow was 900 CFS.

Hail in COCONINO, ARIZONA
From 18-AUG-21 17:50:00 to 18-AUG-21 17:50:00 (MST-7)
Location: NORTH RIM
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Golf ball sized hail (1.75 inches diameter) was reported near the entrance to the North Rim of The Grand Canyon National Park.

Flash Flood in YAVAPAI, ARIZONA
From 18-AUG-21 17:30:00 to 18-AUG-21 20:15:00 (MST-7)
Location: IRON SPGS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Granite Creek in Prescott (GCRA3) rose from 7.17 to 10.22 feet in 45 minutes.

Flash Flood in NAVAJO, ARIZONA
From 18-AUG-21 17:00:00 to 18-AUG-21 19:00:00 (MST-7)
Location: FOREST LAKE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Pictures on social media show at least 10 inches of water flowing in Dinnebito Wash near Hardrock. The water had been flowing for at least 2 hours. Road going into Hardrock were not passible due to the water flowing over the roadways.

Flash Flood in YAVAPAI, ARIZONA
From 18-AUG-21 17:36:00 to 18-AUG-21 21:20:00 (MST-7)
Location: ENTRO
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Granite Creek (GRWA3) below Watson Lake rose 2.2 feet to 3.97 feet in one hour and 44 minutes. Water crested at 7:20 PM MST.

Flash Flood in YAVAPAI, ARIZONA
From 18-AUG-21 22:08:00 to 18-AUG-21 23:13:00 (MST-7)
Location: MONTEZUMA CASTLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The Wet Beaver Creek gauge (BCMA3) near Montezuma Castle National Monument rose from 1.0 to 3.03 feet in 65 minutes.  It crested at 11:13 PM MST.

Flash Flood in YAVAPAI, ARIZONA
From 18-AUG-21 20:40:00 to 19-AUG-21 08:00:00 (MST-7)
Location: SYCAMORE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The Verde River near Clarkdale rose over 17 feet in 58 minutes (VDCA3). The water crested at 19.49 feet at 942 PM MST.

Flash Flood in YAVAPAI, ARIZONA
From 19-AUG-21 05:30:00 to 19-AUG-21 14:30:00 (MST-7)
Location: AULTMAN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The Verde River near Camp Verde rose just over 10 feet in 4 hours (VAVA3).  The water crested at 14.23 at 9:30 AM MST.

Flash Flood in YAVAPAI, ARIZONA
From 18-AUG-21 19:08:00 to 19-AUG-21 00:00:00 (MST-7)
Location: CANYON
Flood cause: Heavy Rain / Burn Area
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency Management reported a 4 foot rise on Black Canyon Creek at 8:08 PM MST.  This creek is downsteam from parts of the Tiger Fire (2021).