Plentiful tropical moisture spread into central Arizona ahead of a tropical depression named 16-E, creating a very moist and unstable atmosphere. As a low pressure system moved eastward across Arizona on September 22nd, scattered thunderstorms developed and some of the stronger storms generated intense rainfall which produced episodes of both urban flooding and flash flooding in the greater Phoenix area during the evening hours. Some of the more significant flooding affected communities such as Scottsdale, Mesa and Apache Junction. Urban Flood Advisories and Flash Flood Warnings were issued for portions of the greater Phoenix area as a result of the flooding. Fortunately, no injuries were reported.

Flash Flood in MARICOPA, ARIZONA
From 22-SEP-15 18:00:00 to 22-SEP-15 21:00:00 (MST-7)
Location: SCOTTSDALE MUNI
Flood cause: Heavy Rain
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Newspaper

Plentiful tropical moisture was in place across the greater Phoenix area on September 22nd; the moisture spread into Arizona ahead of tropical depression 16-E located to the southeast of Arizona. As a low pressure system moved east across the central deserts, scattered thunderstorms developed and they affected the community of Scottsdale. Due to the high moisture content in the atmosphere, the storms produced intense rainfall with rates well in excess of 1 inch per hour. The heavy rain led to both urban street flooding as well as isolated occurrences of flash flooding in the Scottsdale area. According to an article in the Arizona Republic, heavy rains during the evening hours quickly flooded washes in central Scottsdale, just west of Highway 101 near Cactus Road. One flooded wash turned into a river, flooding homes in the area near 84th Street and Cactus Road. Water flooded into the home of Sonny Friedman, filling the floor with several inches of water and causing significant damage. The damaged home had an area of nearly 5000 square feet.

Heavy Rain in MARICOPA, ARIZONA
From 22-SEP-15 17:30:00 to 22-SEP-15 20:00:00 (MST-7)
Location: SCOTTSDALE MUNI
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Significant tropical moisture was present across the greater Phoenix area on September 22nd; the moisture spread into the area ahead of tropical depression 16-E which passed by Arizona to the southeast. A passing low pressure system acted on the moisture and scattered thunderstorms resulted, some of which affected Scottsdale. Due to the high moisture content, some of the storms produced very heavy rainfall with peak rain rates greater than 1 inch per hour. The heavy rain resulted in episodes of urban street flooding and led to the issuance of an Urban and Small Stream Flood Advisory for Scottsdale at 1800MST. According to a trained spotter 5 miles southwest of central Scottsdale, the street flooding caused water to rise above curb level on Hayden Road throughout Scottsdale Muni Airport, and along Thunderbird Road between Hayden Road and 64th Street. Street flooding was also present along Sweetwater from 60th Street to 64th Street. In some locations, traffic was barely able to pass through the deepest locations where the water is flowing. The flooding as reported by the spotter occurred around 1800MST.

Flash Flood in MARICOPA, ARIZONA
From 22-SEP-15 19:00:00 to 22-SEP-15 21:30:00 (MST-7)
Location: TWIN KNOLLS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The atmosphere across the greater Phoenix area was very moist and unstable on September 22nd, courtesy of tropical moisture that spread into the area ahead of tropical depression 16-E. An area of low pressure moved across central Arizona during the evening hours and as a result scattered thunderstorms developed which affected the eastern portions of the Phoenix area, including the community of Mesa. Due to the high levels of moisture in the atmosphere, some of the stronger storms produced intense rainfall with peak rain rates approaching 2 inches per hour. The intense rain led to episodes of both urban flooding and flash flooding. According to a trained weather spotter, the exit ramps on the Superstition Highway at Crimson Road became flooded by 1920MST. The flooding was caused by 1.4 inches of rain which fell in the hour ending at 1920MST. About 12 to 18 inches of rain covered the roadway in this area, approximately 4 miles southeast of Superstition Springs Mall. A Flash Flood Warning was issued at 1923MST and it remained in effect through 2115MST. No injuries were reported due to the flash flooding.