Flash Flood and Hail in Arizona, July 9, 2018

Strong thunderstorms developed across the greater Phoenix metropolitan area as well as higher terrain areas northeast of Phoenix during the afternoon hours on July 9th. The stronger storms generated gusty outflow winds in excess of 60 mph at times. An automated weather station located at Horseshoe Dam measured a wind gust of 63 mph at 1512MST.

Strong thunderstorms developed across the eastern portion of the greater Phoenix area during the afternoon hours on July 9th. A few of the stronger storms generated large hail ranging between one quarter and three quarters of an inch in diameter, affecting the communities of Mesa and Apache Junction. According to a trained weather spotter located about 3 miles east of East Mesa, dime to penny sized hail fell near the intersection of Ellsworth Road and Highway 60. At roughly the same time, another trained spotter 3 miles west of Apache Junction reported similar sized hail near the intersection of Broadway Road and Signal Butte. No damage was reported due to the large hail. A few other hail reports were received in the area but the diameters were smaller, closer to one quarter of an inch.

Strong thunderstorms developed over eastern portions of the greater Phoenix area during the afternoon hours, and they produced strong, gusty and damaging outflow winds that affected portions of East Mesa. According to a report from local broadcast media, at 1540MST winds estimated to be at least 60 mph caused damage to a mobile home park located about 3 miles east of East Mesa. The damage was near the intersection of Broadway and Ellsworth Roads. No injuries were reported due to the wind damage.

Scattered thunderstorms developed over eastern portions of the greater Phoenix area during the afternoon hours and some of them affected the community of Gilbert. The more intense storms produced gusty and damaging outflow winds in excess of 50 mph. According to a trained weather spotter located about 3 miles northeast of Gilbert, at 1545MST strong winds downed several trees in the area near the intersection of Baseline and Greenfield Roads. Wind gusts were estimated to be as high as 60 mph. No injuries were reported due to the strong winds.

Scattered thunderstorms developed across the eastern portion of the greater Phoenix area, including the community of Mesa, during the afternoon hours on July 9th. Some of the storms produced gusty and damaging outflow winds in excess of 60 mph. According to a public report, at 1550MST gusty winds estimated to be nearly 65 mph downed several large trees which were located between University Drive and Main Street, just east of Center Street. Shortly thereafter, at 1605MST, local broadcast media reported trees and power lines downed by the strong winds approximately 1 mile northeast of Mesa, near the intersection of Mesa Drive and East 8th Street.

Strong thunderstorms developed across the eastern portions of the greater Phoenix area, including the community of Mesa, during the afternoon hours on July 9th. The stronger storms generated gusty and damaging outflow winds in excess of 60 mph. According to a trained weather spotter in central Mesa, at 1555MST winds estimated to be at least 65 mph downed several trees and damaged a garage. The damage was just northeast of the intersection of east Brown Road and Mesa Drive. No injuries were reported due to the strong winds.

Strong thunderstorms developed over central portions of the greater Phoenix area, including the community of Tempe, during the afternoon hours on July 9th. Some of the storms generated gusty outflow winds in excess of 50 mph. According to a public report, at about 1600MST outflow winds estimated to be 60 mph in strength blew down a large tree near the intersection of University Avenue and McClintock Road, about 1 mile northeast of Arizona State University. No injuries resulted from the falling tree.

Thunderstorms with very heavy rain developed across the central and northern portions of the greater Phoenix area, including the community of Paradise Valley, during the late afternoon and evening hours on July 9th. The stronger storms produced intense rainfall with peak rain rates well in excess of one inch per hour. The heavy rain led to episodes of street flooding; at 1623MST a trained weather spotter located 1 mile east-southeast of Paradise Valley reported very heavy rain with curb to curb street flooding near the intersection of Scottsdale Road and McDonald Drive. An Urban Flood Advisory was issued for the area shortly afterwards at 1647MST and it remained in effect until 1845MST.

Scattered thunderstorms developed across the eastern portion of the greater Phoenix area during the afternoon hours on July 9th and some of the stronger storms produced gusty and damaging outflow winds in excess of 50 mph. One strong storm impacted the community of East Mesa. According to a trained weather spotter 4 miles west of East Mesa, gusty winds estimated to be upwards of 60 mph damaged a carport just northeast of the intersection of East Main Street and north Val Vista Drive. The extent of the damage was not reported.

Scattered thunderstorms developed over the eastern portion of the greater Phoenix area, including the community of Mesa, during the afternoon hours on July 9th. The stronger storms generated very damaging microburst wind gusts well in excess of 60 mph. According to a trained weather spotter in Mesa located just northeast of the intersection of Broadway Road and Stapley Drive, gusty microburst winds estimated to be at least 80 mph knocked down numerous trees with diameters of at least 6 inches. In addition, a strong gust peeled back part of the roof of a house near the intersection of Jarvis Avenue and Barkley Road. No injuries were reported due to the strong winds.

Strong thunderstorms developed across the eastern portion of the greater Phoenix area, including the community of Mesa, during the afternoon hours on July 9th. The storms generated strong and gusty outflow winds in excess of 60 mph at times. One strong storm affected the central portion of Mesa. According to a local broadcast media report, strong microburst winds estimated to be near 70 mph caused a large tree to blow over and fall onto a house. The house was near the intersection of north Center Street and east 8th Street. The fallen tree required the rescue of a male resident of the house and there was one known injury.

Scattered thunderstorms affected the central portions of the greater Phoenix area, including downtown Phoenix and areas around Sky Harbor Airport, during the afternoon hours on July 9th. A few of the stronger storms generated very strong and damaging microburst winds. According to a report from local broadcast media, at 1630MST a microburst occurred about 1 mile northwest of Sky Harbor Airport and it was estimated by damage to be as high as 90 mph. The strong winds tore off large sections of an apartment complex roof which resulted in a serious injury to an occupant. A few minutes after the damage occurred, a wind gust of 71 mph was measured nearby by the official ASOS weather station at Sky Harbor Airport.

Scattered thunderstorms developed in the greater Phoenix area during the afternoon hours on July 9th and some of the stronger storms produced gusty outflow winds in excess of 50 mph. One of these storms generated strong outflow winds in the town of Scottsdale. At 1634MST, the official ASOS weather station located at the Scottsdale Airport measured a wind gust of 59 mph.

Scattered thunderstorms moved across the western portion of the greater Phoenix area during the late afternoon hours on July 9th and they produced gusty and damaging outflow winds. The winds downed a number of trees across the Glendale area within about a 30 minute period. At 1635MST a trained weather spotter 4 miles northeast of Glendale reported a large tree downed by thunderstorm outflow winds. The downed tree was northeast of the intersection of Dunlap Avenue and 35th Avenue. At 1700MST another trained spotter 5 miles south of Glendale reported another large tree downed near the intersection of 51st Avenue and McDowell Road. Finally, at 1712MST a trained spotter 2 miles southwest of Glendale reported a tree with a 10 inch diameter trunk blown down and blocking 75th Avenue near Missouri Avenue. Wind gusts in all cases were estimated to be near 60 mph in strength. No injuries were reported due to falling trees.

Scattered thunderstorms moved across the western portion of the greater Phoenix area during the late afternoon hours on July 9th and they produced gusty and damaging outflow winds. The winds downed a number of trees across the Glendale area within about a 30 minute period. At 1635MST a trained weather spotter 4 miles northeast of Glendale reported a large tree downed by thunderstorm outflow winds. The downed tree was northeast of the intersection of Dunlap Avenue and 35th Avenue. At 1700MST a member of the public 5 miles south of Glendale reported another large tree downed near the intersection of 51st Avenue and McDowell Road. Finally, at 1712MST a trained spotter 2 miles southwest of Glendale reported a tree with a 10 inch diameter trunk blown down and blocking 75th Avenue near Missouri Avenue. Wind gusts in all cases were estimated to be near 60 mph in strength. No injuries were reported due to falling trees.

Strong thunderstorms developed across the central portions of the greater Phoenix area during the afternoon hours on July 9th. Some of the storms produced very strong microburst winds in excess of 60 mph. At 1638MST the official ASOS weather station at Phoenix Sky Harbor Airport measured a wind gust of 71 mph.

Strong thunderstorms developed over the northern portion of the greater Phoenix area, including the community of Deer Valley, during the afternoon hours on July 9th. Some storms produced strong outflow winds in excess of 50 mph. At 1642MST, The official ASOS weather station at the Deer Valley airport measured a wind gust to 64 mph.

Thunderstorms developed across the central portion of the greater Phoenix area, including downtown Phoenix, during the afternoon hours on July 9th. Some of the stronger storms generated gusty and damaging microburst type outflow winds, well in excess of 60 mph at times. According to a trained weather spotter located about 2 miles northwest of central Phoenix, at 1645MST outflow winds estimated at 75 mph blew a 25 foot section of roof off of a building. The building was located near north 19th Avenue and west Holly Street. This was just east of Grande Avenue and north of McDowell Road. No injuries were reported due to the damaged building.

Thunderstorms developed across the northern portion of the greater Phoenix area, including the area around Deer Valley, during the late afternoon hours on July 9th. Some of the stronger storms generated gusty outflow winds in excess of 60 mph. According to a report from the public, at 1645MST gusty winds estimated up to 70 mph downed numerous trees in a local neighborhood. In addition, they tore a solar panel from a roof. The damage occurred about 7 miles northwest of the Deer Valley Airport, in an area just west of Pyramid Peak Parkway and north of Happy Valley Road.

Scattered thunderstorms developed over the northern portion of the greater Phoenix area, including the community of Deer Valley, during the afternoon hours on July 9th. Some of the stronger storms generated gusty damaging outflow winds in excess of 50 mph. According to a trained spotter located 6 miles east of Deer Valley, strong wind gusts estimated to be upwards of 65 mph uprooted a tree with a 7 inch diameter trunk. The damage occurred on Beardsley Road, just east of Coyote Basin Park.

Thunderstorms with very heavy rain developed across the central portion of the greater Phoenix area during the late afternoon hours. The heavy rain affected locations from around downtown Phoenix northeast to the Phoenix Country Club. At 1659MST a trained weather spotter 3 miles northeast of central Phoenix reported that 1.2 inches of rain fell within 35 minutes near the intersection of 16th Street and Thomas Road. The heavy rain led to episodes of street flooding throughout central Phoenix into the early evening hours. At about 1700MST a nearby trained spotter reported street flooding with water over the curbs and reaching into some yards near 16th Street and Indian School Road. At the same time a report from the public was received indicating water over 3 inches deep was flowing over sidewalks and into yards. This was occurring just northeast of the intersection of Highway 51 and Interstate 10. Additionally, at 1719MST a trained spotter reported curb to curb street flooding at City Hall in downtown Phoenix. Flash flood warnings were not issued, however an Urban Flood Advisory was issued for the area at 1647MST and it remained in effect through 1845MST.

Thunderstorms developed across the western portion of the greater Phoenix area, including the community of Peoria, during the late afternoon hours on July 9th. Some of the stronger storms generated gusty and damaging outflow winds in excess of 50 mph. According to a trained weather spotter 1 mile east-southeast of Peoria, gusty winds downed a large tree and also blew off a number of roof shingles from a nearby building. This was near the intersection of north 75th Avenue and west Mission Lane. At about the same time, another trained spotter 2 miles southwest of Peoria indicated that several trees were downed near the intersection of the loop 101 and Olive Avenue. In both cases, wind gusts were estimated to be at least 60 mph in strength.

Thunderstorms developed across the northern portion of the greater Phoenix area, including the town of Deer Valley, during the late afternoon hours on July 9th. The stronger storms generated gusty and damaging outflow winds in excess of 60 mph. According to a trained weather spotter 5 miles west of Deer Valley, gusty winds to near 65 mph downed a large tree. No injuries were reported. The downed tree was located just northeast of the intersection of 67th Avenue and the Loop 101.

Scattered thunderstorms developed across the western portion of the greater Phoenix area during the afternoon hours on July 9th and a few of the stronger storms generated gusty outflow winds in excess of 50 mph. At 1708MST the official ASOS weather station at Luke Air Force Base measured a wind gust of 60 mph.

Thunderstorms developed across the western portion of the greater Phoenix area during the late afternoon hours and some of the stronger storms produced gusty outflow winds in excess of 50 mph. According to a trained weather spotter located about 2 miles northwest of Citrus Park, at 1715MST thunderstorm wind gusts estimated as high as 60 mph blew off a number of roof tiles on a home. The home was northwest of Luke Air Force Base and east of the White Tank Mountains, and just northeast of the intersection of Olive Avenue and north Perryville Road.

Thunderstorms with heavy rainfall developed across the central portions of the greater Phoenix area, including around Laveen and South Mountain, during the late afternoon and early evening hours on July 9th. The stronger storms produced intense rainfall with peak rain rates in excess of 2 inches per hour. The heavy rain led to episodes of street flooding and flash flooding. According to a trained weather spotter located 5 miles northwest of Ahwatukee Foothills, at 1730MST street flooding had developed near the intersection of Dobbins Road and 27th Avenue. Irrigation canals in the area were reported to be overflowing and area streets were said to be impassable. Later in the evening, around 1945MST, county officials reported flash flooding 7 miles southwest of central Phoenix, in the area around Baseline Road and 43rd Avenue; the flooding was reported to extend south to Dobbins Road. The flash flooding involved flooded roadways, some of which were impassable. A Flash Flood Warning was issued for the area at 1722MST and it remained in effect until 2015MST.

Thunderstorms developed across the northwest portion of the greater Phoenix area, including the town of Sun City, during the late afternoon and early evening hours on July 9th. The stronger storms generated gusty and damaging outflow winds in excess of 60 mph. According to a trained weather spotter located about 3 miles north of Sun City, gusty outflow winds estimated to be as high as 70 mph knocked down a tree with an 8 inch diameter trunk. The downed tree was partially blocking Beardsley Road near 95th Avenue. No accidents were reported due to the tree obstructing traffic on the road.