Copious amounts of tropical moisture spread north and into south-central Arizona during the morning hours on September 23rd, leading to widespread showers and thunderstorms. Some of the stronger storms generated intense rain with peak rain rates between 1 and 2 inches per hour. Storms and heavy persisted through the afternoon and into the evening and resulted in several episodes of flash flooding across the central deserts to the west and northwest of Phoenix. Multiple stream gauges from the Maricopa County Flood Control District indicated that washes and streams rapidly filled with water during flash flooding, easily exceeding their alarm or bankfull stages and causing the flooding of various roads and low water crossings. The reports were generally received from very open country. Additionally, at 1633MST Arizona Department of Highways reported that Eagle Eye Road 10 miles southeast of Gladden, in far northwest Maricopa County, became closed due to debris that washed over the road from the flash flooding. There were no reports of accidents or injuries due to the flash flooding. In 2020, the Arizona Department of Transportation was awarded $10.7 million from the Federal Highway Administration to support the repair of roads and bridges damaged due to the numerous flash flooding events that occurred across Arizona on the 23rd.

Flash Flood in MARICOPA, ARIZONA
From 23-SEP-19 11:45:00 to 23-SEP-19 15:40:00 (MST-7)
Location: WITTMANN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Scattered to numerous showers and thunderstorms continued to develop across the northern portions of the Phoenix area through late morning and into the afternoon hours on September 23rd, and some of the storms continued to produce very heavy rain with peak rain rates well in excess of one inch per hour. The heavy rain led to episodes of flash flooding, one of which occurred about 5 miles to the northeast of Wittmann and near Highway 74. According to data from the Picacho Wash Maricopa County Flood Control District stream gauge (ID #5678), rapidly rising waters exceeded the bank full flood levels, reaching a stage of 4.36 feet. Bank full stage was 4 feet. There were no reports of any accidents due to the flash flooding. A Flash Flood Warning was issued and was in effect at the time of the report.

Flash Flood in MARICOPA, ARIZONA
From 23-SEP-19 13:15:00 to 23-SEP-19 18:30:00 (MST-7)
Location: CIRCLE CITY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Scattered to numerous showers and thunderstorms developed across the northern and western portions of the greater Phoenix area during the late morning, and they continued into the afternoon. Some of the storms generated locally heavy rains with peak rain rates well in excess of one inch per hour. The heavy rains led to episodes of flash flooding, some of which occurred over rather open country such as the Hassayampa Plain well to the northwest of Phoenix. The flash flooding resulted in rapid rises in area washes, causing them to quickly exceed alarms stages. At 1348MST a flood control district stream gauge along Daggs Wash and West Peak View Road indicated that water quickly exceeded both alarm and bank full stages. The flash flooding resulted in quick inundation of area low water crossings. The gauge was located roughly 10 miles southwest of Circle City. A Flash Flood Warning was issued for the area at 1326MST and was in effect at the time of the flooding. No injuries were reported due to the flash flooding.

Flash Flood in MARICOPA, ARIZONA
From 23-SEP-19 19:20:00 to 24-SEP-19 00:15:00 (MST-7)
Location: TONOPAH
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Scattered to numerous showers and thunderstorms continued to develop across the central deserts to the west of Phoenix during the afternoon and early evening hours on September 23rd, and the stronger storms produced very heavy rain with peak rain rates well in excess of one inch per hour. The heavy rain led to an episode of flash flooding west of Phoenix near the town of Tonopah; at 2010MST mesonet data from a Maricopa County Flood Control District stream gauge indicated that flood waters rapidly climbed above alarm and bank full stages in the Delaney Wash. The gauge was located roughly 3 miles south of Tonopah. The flash flooding resulted in the road closures of the Salome Highway and the 411th Avenue Road crossing. A Flash Flood Warning was issued for the area prior to the report; no injuries were reported due to the flash flooding.

Flash Flood in MARICOPA, ARIZONA
From 23-SEP-19 13:30:00 to 23-SEP-19 18:30:00 (MST-7)
Location: AGUILA
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Department of Highways

Scattered to numerous showers and thunderstorms continued to develop across western Maricopa County during the afternoon hours on September 23rd and some of the storms produced intense rainfall with peak rain rates well in excess of 1 inch per hour. The very heavy rain led to flash flooding well to the west of Phoenix and near the La Paz County line during the late afternoon. According to the Arizona Department of Highways, at 1633MST flash flooding caused debris to flow across Eagle Eye Road and as a result the road was closed. This occurred roughly 10 miles to the southeast of Gladden and just to the east of the La Paz County line. Fortunately there were no accidents or injuries associated with the debris over the road. Although a Flash Flood Warning was in effect at the time, it was for an area to the east of where the flooding actually occurred.