Flash Flooding and Heavy Rain in Arizona, August 19 to 21, 2014

Showers and thunderstorms developed across the western and northern portions of the greater Phoenix metropolitan area after 0600MST, and they continued to intensify and move northeast into the mid morning hours on August 12th. The stronger storms produced locally heavy rain with rainfall rates between one and two inches per hour. The rain led to significant urban flooding; at 0712MST a west valley trained spotter 5 miles southwest of Beardsley measured 1.38 inches of rain within 35 minutes. He indicated that significant ponding was occurring on area roads. At 0647MST another trained spotter 2 miles northeast of Sun City West estimated one inch of rain in about one hour.

Thunderstorms developed across western and northern portions of the greater Phoenix metropolitan area after 0600MST on August 19th, and they continued to intensify and move northeast into the middle of the morning. The stronger storms generated very heavy rain with rainfall rates between one and two inches per hour and the heavy rain led to significant urban flooding. The heavy rain affected communities such as Peoria and Deer Valley. At 0703MST, a trained weather spotter 6 miles west of the Deer Valley airport measured 1.75 inches of rain within 45 minutes. The heavy rain led to significant urban flooding in the area, and an Urban and Small Stream Flood Advisory was issued at 0627MST.

Thunderstorms developed across central and northern portions of the greater Phoenix metropolitan area after 0600MST on August 19th, and they continued to intensify and move towards the northeast, producing locally heavy rainfall. Some of the communities affected included Deer Valley, Desert Ridge Marketplace and Scottsdale. The stronger storms generated rainfall rates between one and two inches per hour which led to significant urban flooding. At 0722MST, a trained spotter 5 miles northwest of Desert Ridge Marketplace, near the Cave Buttes recreational area, measured 0.93 inches of rain within 30 minutes which represented a nearly two inch per hour rainfall rate. Street flooding was occurring in the area. Another trained spotter located about 3 miles southwest of Desert Ridge Marketplace measured 1.32 inches of rain between 0630MST and 0730MST. The urban flooding led to the issuance of an Urban and Small Stream Advisory at 0627MST.

Thunderstorms developed across the central and northern portions of the greater Phoenix metropolitan area during the morning rush hour, and they steadily intensified as they moved towards the northeast. The stronger storms produced very heavy rain with peak rain rates approaching 2 inches per hour. The intense rain led to flash flooding, affecting communities such as Deer Valley and North Mountain Park as well as the Interstate 17 corridor. At 0726MST, a trained spotter about 3 miles of North Mountain Park reported a flash flood; he indicated that there was 3 feet of water in the Cave Creek wash near the intersection of 7th Avenue and Coral Gables Drive. Additionally, at 0717MST, local broadcast media reported that the underpass was flooded at the intersection of Interstate 17 and Greenway Road. Finally, another trained weather spotter reported multiple low water crossings flooding in the area around Desert Ridge Marketplace. No injuries were reported due to the flash flooding.

Thunderstorms developed across the northern portion of the greater Phoenix metropolitan area during rush hour on August 19th, and they steadily intensified and moved to the northeast, affecting the Interstate 17 corridor from Deer Valley and Happy Valley Road northward towards Anthem. The stronger storms produced very heavy rain with peak rain rates of around 2 inches per hour. The heavy rain led to flash flooding which affected motorists on Interstate 17 south of Anthem. At around 0700MST, a trained weather spotter reported widespread curb-to-curb flooding across the interstate, south of Anthem and in the area around Daisy Mountain. At 0705MST, Phoenix Fire and Rescue reported a water rescue just west of Interstate 17 and north of Happy Valley Road. No injuries were reported due to the flash flooding.

Thunderstorms developed across the northern portion of the greater Phoenix area during the early morning on August 19th, and continued to intensify and move northeastward in waves through the late morning and into the afternoon hours. The stronger storms produced locally heavy rain with rain rates in excess of two inches per hour at times. The heavy rain led to episodes of flash flooding which especially impacted the Interstate 17 corridor from Anthem northward through new River and up to Black Canyon City. Multiple water rescues were needed along the I-17 corridor starting shortly after 0700MST. At 0714MST, Phoenix Fire and Rescue reported a water rescue in New River near I-17. At 1000MST, a trained weather spotter 8 miles north of New River reported a rockslide on I-17 due to flash flooding. At the same time, another weather spotter 4 miles north of New River reported that Interstate 17 was completely inundated with water across the entire width of the highway; multiple cars were stranded and water rescues were underway. At 1150MST, Phoenix Fire and Rescue reported yet another water rescue underway 2 miles northwest of New River. Additionally, at 1213MST Phoenix Fire and Rescue indicated that another water rescue was needed 2 miles northwest of the town of Anthem along the I-17 corridor. One of the more dramatic water rescues was detailed in a story posted on the Channel 5 KPHO website; the rescue occurred at a home in New River. The home, located at 46100 North 43rd Avenue, became surrounded by raging floodwaters and soon was swept off of its foundation. It drifted 20 feet or so with the waters and became lodged between 2 trees. A woman and another occupant were trapped and a helicopter lowered 2 rescuers to the roof of the house. However, they were unable to rescue the trapped people until an hour or so later after the floodwaters receded. The home was a total loss, and the owner also lost 2 cars and a motorcycle to the raging water. Other homes and businesses in the New River area suffered damage due to flash flooding. A story posted on the AP website indicated that a horse property was destroyed by the flood waters. A muddy pit filled with rocks, pieces of asphalt and mangled trees were all that remained of a circular horse pen. Fortunately, no injuries were reported due to the significant and widespread flash flooding episodes.

Thunderstorms developed across the northern and northeast portions of the greater Phoenix area during the early morning hours on August 19th, and they intensified and moved northeastward through the morning hours and into the afternoon. The stronger storms produced locally heavy rain with rain rates in excess of 2 inches per hour at times; the intense rain was partly due to lifting in the lower atmosphere as storms moved from the lower deserts northeast into higher terrain. The heavy rain led to episodes of flash flooding which necessitated multiple water rescues from Phoenix Fire and Rescue. Some of the areas that experienced the most significant flooding included Carefree and Cave Creek. Between 0731MST and 0740MST, multiple swift water rescues were performed by Phoenix Fire in the areas around Cave Creek. Also, at 0813MST, Phoenix Fire and Rescue reported another water rescue about 4 miles northwest of Desert Ridge Marketplace. Fortunately, no injuries were reported due to the flash flooding.

Widespread showers and thunderstorms developed across the northern portion of the greater Phoenix metropolitan area during the morning hours on August 19th, and they continued to intensify and move to the northeast into the early afternoon hours. The storms produced periods of heavy rain with peak rainfall rates in excess of 2 inches per hour. The heavy rain led to flash flooding which especially impacted the communities of Anthem and New River. According to a story posted on the AP website, flood waters raging down Skunk Creek inundated the Cox Cactus farm located at 1537 West Desert Hills Drive in Phoenix. The cactus nursery, on the east side of Anthem, lost nearly two million dollars in inventory and the owners estimated that it would take nearly two years to recover from the storm.

Scattered thunderstorms continued to develop across the north and west portions of the greater Phoenix metropolitan area during the late morning hours on August 19th, affecting communities such as Surprise, Beardsley and Wittmann. The stronger storms produced locally heavy rainfall, with peak rain rates in excess of one inch per hour. The heavy rain led to urban flooding as well as flash flooding. At 1119MST, Phoenix Fire and Rescue reported flash flooding about 2 miles southeast of Wittmann; the Phoenix fire department was dispatched to assist with a water rescue. Also, at 1131MST, Phoenix Fire and Rescue reported another water rescue in progress about 4 miles north of the community of Beardsley. No injuries were reported due to the flooding. At the time, a Flash Flood Warning was not in effect, rather an Urban and Small Stream Flood Advisory had been issued for the area.

Thunderstorms with locally heavy rain redeveloped across the central portions of the greater Phoenix metropolitan area during the evening hours on August 19th and they affected the community of Scottsdale. Due to previous heavy rain in the area, additional rains easily led to flash flooding; according to an article posted on the Channel 5 website, four people and a dog were rescued from a flooded wash in Scottsdale during the evening hours. One of the four people was a woman in a wheelchair; their vehicle became stuck in the flooded Indian Bend wash in Eldorado Park. No injuries were reported due to the flash flooding.