Flash Flooding and Heavy Rain in Arizona, July 21, 2013

A large area of showers and thunderstorms developed across the central Arizona deserts during the morning hours on July 21st, and they affected portions of southwest Maricopa county extending from Gila Bend eastward into Pinal county. The storms persisted into the late morning and they generated locally heavy rains with rainfall rates between one and two inches per hour. For exmaple, at 714 am a trained spotter 6 miles west of Stanfield reported 0.58 inches of rain fell in just 10 minutes, causing streams in the area to run heavily. An Urban and Small Stream Flood Advisory was issued for southwest Maricopa county at 655 am, continuing until 845 am. At 950 am, local law enforcement officials reported that State Route 283 between the town of Maricopa and Gila Bend had been barricaded by sheriff's deputies due to flash flooding. The heavy rains over central Arizona started around 6 am, and since the flooding occurred less than 6 hours later, it is considered to be flash flooding. No Flash Flood Warnings were in effect at the time of the flooding over State Route 238.

Scattered to numerous showers and thunderstorms developed across south central Arizona, inculding the greater Phoenix area, during the morning hours on July 21st. The thunderstorms increased in intensity as the morning progressed and they produced locally heavy rain with rainfall rates in excess of one inch per hour as depicted by area rain gages and radar rainfall estimates. According to a trained weather spotter located 1 mile northeast of Ahwatukee, 0.70 inches of rain was measured in a 30 minute period ending at 935 am. Area dry washes were running heavy due to the rainfall. Additionally, the official ASOS rain gage at Phoenix Sky Harbor Airport measured 0.88 inches of rain in a 43 minute period ending at 1058 am. The heavy rain led to significant urban street flooding and caused area washes to run heavily. An Urban and Small Stream Flood Advisory was issued for the greater Phoenix area at 1004 am and it remained in effect through about noon. Additional rains continued into the afternoon hours and they were heavy at times.

Scattered to numerous showers and thunderstorms developed across portions of south central Arizona during the morning hours on July 21st, and they increased in coverage and intensity as the morning progressed. Locally heavy rain was common with the thunderstorms and gage reports and radar indicated rain rates between one and two inches per hour. By 10 am, an Urban and Small Stream Flood Advisory was issued for portions of central Phoenix including Paradise Valley, and the advisory was extended to include all of Scottsdale by 11 am. Urban and Small Stream Flood Advisories continued for Scottsdale through 130 pm. According to a trained weather spotter, as of 1145 am, numerous streets had been flooded across far northern Scottsdale, in the area north of the loop near Tatum Road and East Dynamite. In addition, local law enforcement indiated that there were numerous street closures due to flooding across central Scottsdale, from McDonald Road north to Frank Lloyd Wright Boulevard. Since the flooding occurred less than 6 hours from the causative heavy rains, it is considered to be flash flooding. Additional rains continued across Scottsdale into the afternoon hours and another flood advisory was later issued at 312 pm which continued until 5 pm.

Scattered to numerous showers and thunderstorms developed across the south central deserts during the morning hours on July 21st and they became more intense and numerous as the morning progressed. By late morning, thunderstorms were widespread across the northeast parts of the greater Phoenix area, including Scottsdale, and rain rates between one and two inches per hour were indicated by rain gage reports and radar estimates. An Urban and Small Stream Flood Advisory was initially issued for the Scottsdale area beginning around 11 am and it continued until 130 pm. The heavy rains led to significant flooding and flash flooding across Scottsdale, numerous roads were inundated and closed and area washes, including the Indian Bend Wash, ran heavily. According to an article posted on-line at azcentral.com, multiple swift water rescues were needed in north Scottsdale. In one rescue, crews extricated two people whose vehicle became stuck near Scottsdale Road and Sutton Drive. In a much more significant rescue, Scottsdale crews utilized rescue swimmers to save a stranded motorist near 83rd Street and Desert Cove Avenue. More than 25 firefighters from Tempe, Phoenix and Scottsdale responded to the scene according to Scottsdale battalion chief David Folio. Additionally, a Paradise Valley woman was rescued after her vehicle was stuck near Tatum Boulevard and Desert Park Place according to Phoenix Fire Captain Larry Nunez. Times for the rescues were unspecified in the articles, but likely occurred sometime from late morning into early afternoon. Although Flash Flood Warnings were not issued for Scottsdale during this event, another Urban and Small Stream Flood Advisory was later issued at 312 pm and it continued until 5 pm.

Scattered to numerous showers and thunderstorms developed across the south central deserts during the morning hours on July 21st and they became more intense and numerous as the morning progressed. By late morning, thunderstorms were widespread across the northeast parts of the greater Phoenix area, including Scottsdale, and rain rates between one and two inches per hour were indicated by rain gage reports and radar estimates. An Urban and Small Stream Flood Advisory was initially issued for the Scottsdale area beginning around 11 am and it continued until 130 pm. The heavy rains led to significant flooding and flash flooding across Scottsdale, numerous roads were inundated and closed and area washes, including the Indian Bend Wash, ran heavily. According to an on-line article posted at azcentral.com, Eldorado Park was hit hard according to Sandy Hlebaen of the Scottsdale Parks and Recreation Department. Eldorado park runs along the Indian Bend Wash east of Scottsdale Road. Bike paths, sidewalks and picnic benches were filled with debris from the wash. Video clips showed the wash running angrily and heavily with churning water. No injuries were reported due to the flooding. An additional Flood Advisory was issued for Scottsdale, beginning at 312 pm and continuing until 5 pm, so the wash was most likely flowing heavily into the afternoon or even the early evening hours.

Scattered to numerous showers and thunderstorms developed across the south central deserts during the morning hours on July 21st and they became more intense and numerous as the morning progressed. By late morning, thunderstorms were widespread across the northeast parts of the greater Phoenix area, including Scottsdale and Paradise Valley, and rain rates in excess of two inches per hour were indicated by rain gage reports and radar estimates. According to county officials, a Maricopa County Flood Control District rain gage on East Doubletree Ranch Road near North Scottsdale Road in central Scottsdale measured 1.65 inches of rain within 30 minutes ending at 1111 am. A Flood Control rain gage on Shea Boulevard near Highway 51 in Paradise Valley measured 1.97 inches of rain within 30 minutes ending at 1120 am. Also, a flood control gage in Cave Creek measured 1.73 inches of rain in one hour, ending at 1144 am. The heavy rain led to multiple road closures across northeast parts of the greater Phoenix area including Scottsdale and it led to multiple swift water rescues. Although Flash Flood Warnings were not issued for Scottsdale, Urban and Small Stream Flood Advisories were issued beginning at about 10 am and continuing through 130 pm. Another Flood Advisory was later issued for Scottsdale at 312 pm which continued through 5 pm.

Scattered to numerous showers and thunderstorms moved across portions of southern Gila county during the late morning and afternoon hours on July 21st, and they produced locally heavy rains with rainfall rates exceeding 2 inches per hour at times. According to a trained weather spotter 7 miles southeast of Tonto National Monument, 0.93 inches of rain was measured within a 14 minute period ending at 1233 pm. The heavy rain led to flooding of washes and streams across southern Gila county and a Flash Flood Warning was issued for portions of west central Gila county beginning at 1252 pm and continuing until 345 pm.

On July 21st, numerous showers and thunderstorms developed during the morning hours across portions of south central Arizona, including the greater Phoenix area, and they intensified into the early afternoon, producing locally heavy rain with rain rates in excess of 2 inches per hour. The heavy rain led to widespread flooding of streets and washes across Apache Junction, which was hit harder by flooding than the surrounding communities. Area spotters reported rain totals between one and two inches within an hour due to the heavy rain. At 1212 pm, an Urban and Small Stream Flood Advisory was issued for Apache Junction and surrounding communities, and this advisory was upgraded to a Flash Flood Warning at 1252 pm. According to a trained weather spotter, at 119 pm flash flooding was occurring in the Weeks Wash in Apache Junction and water was flooding into surrounding residential yards. The flash flooding continued into the early afternoon and a 212 pm, local law enforcement reported that a water rescue took place in Weeks Wash. Apache Junction Firefighters, wading through thigh-high water, rescued 2 people whose pickup truck stalled in the middle of the wash according to Deputy Fire Chief Mike Farber. Additionally, two 19 year old men were trapped in a tree near Lost Dutchman State Park until they were rescued by an Arizona Department of Public Safety helicopter and the Pinal County Sheriff's Office.

On July 21st, numerous showers and thunderstorms developed during the morning hours across south central Arizona including portions of the greater Phoenix area, and they intensified into the early afternoon, producing locally heavy rain with rain rates in excess of 2 inches per hour. The heavy rain led to widespread flooding of streets and washes across Apache Junction, which was hit harder by flooding than the surrounding communities. Area spotters reported rain totals between one and two inches within an hour due to the heavy rain. At 1212 pm, an Urban and Small Stream Flood Advisory was issued for Apache Junction and surrounding communities, and this advisory was upgraded to a Flash Flood Warning at 1252 pm. According to reports from local broadcast media, at 248 pm flash flooding from washes near Tomahawk Road and Superstition Boulevard had spilled into nearby homes and forced several rescues from stranded cars and trucks. The Flash Flood Warning continued until 345 pm and at that time it was changed to a Flood Warning which ran through 645 pm.