- July 31: An intense, slow-moving severe thunderstorm produced heavy rainfall in and around the Anthem community in north-central Maricopa County. The core of the storm remained nearly stationary over Anthem for approximately 70 minutes. Rain gages operated by the Flood Control District and independent weather observers recorded a range of rainfall amounts between 1.38 and 5.01 inches in a 90-minute period, with the highest amount verified by the National Weather Service Phoenix office. The one-hour rainfall in this storm exceeds the Flood Control District's highest recorded one-hour total of 3.58 inches at Vulture Mine Road near Wickenburg on July 21, 1986. Stormwater runoff damaged several homes in Anthem, with up to three feet of flood water inside some of the structures.
- Jan. 19-21: A powerful winter storm system, the strongest since 1993, brings heavy precipitation and causes $4 million in damage. Much of the region receives 1 to 5 inches of total rainfall over three days, with up to 10 inches recorded by District gages in the mountains on the northeastern edge of Maricopa County. Depending on the location, the storm is a 25- to 100-year event, or having a one percent chance of occurring in a year. All major rivers, streams and washes have significant stormwater flow rates. The District's flood control structures function as designed. Cave Buttes Dam has stormwater 62 feet deep in the impoundment pool behind the dam while New River Dam holds back 42 feet. A state of emergency is declared in the county and state. Some roads close due to flooded washes. SRP releases water from upstream reservoirs into the Salt River.
- Sept. 30: The last day of the official 2009 monsoon season brings to a close the fifth driest monsoon in recorded history in the county. In fact, August was the driest in 116 years. The National Weather Service Climate Prediction Center classifies most of Maricopa County as "moderately dry," one step below "severe drought."
- July 13: A surprise, late-afternoon storm hits Tempe, where more than two inches of rain falls in less than two hours. A five-mile section of the U.S. 60 freeway through Tempe is shut down for three hours due to deep standing water across several lanes and beneath underpasses. The Arizona Department of Transportation activates pumps to drain the water.
- July 10: The first major monsoon storm of the season hits with a fury, dropping more rain in a 12-hour period than during the entire 2007 monsoon season. A cluster of severe thunderstorms moved across northwest Maricopa County causing strong winds and dense blowing dust. A second cluster of severe thunderstorms moved into east-central parts of the county and converged over the Phoenix metropolitan area. The highest rainfall totals were in the Wickenburg area (one to three inches), and central Phoenix and northeast Mesa (one to three inches). A total of 0.83 inch was recorded at Phoenix Sky Harbor International Airport, where the runways were shut down for a short period. Areas of street flooding occurred. Rising water forced the closure of Interstate 17 near downtown Phoenix.
- Jan. 27: A day-long rainstorm soaks the county and drops up to three inches of rain in the northeastern mountains. Cave Creek and New River flow rapidly, with 14 feet of water held behind Cave Buttes Dam and 23 feet in the impoundment area behind New River Dam. A dozen roads in Cave Creek, Carefree and North Scottsdale are temporarily impassable due to flooded wash crossings. The Salt River Project (SRP) releases more than 15,000 cubic feet per second of floodwater over Granite Reef Dam into the Salt River through the Phoenix metropolitan area.
- July 31-Aug. 1: Up to three inches of rain falls in parts of the northern Phoenix metropolitan area. Various east-west roads in North Scottsdale are closed due to flooded washes and mud flows. The impoundment pond behind Cave Buttes Dam holds floodwater more than 20 feet deep.
- July 23: Approximately two inches of rain falls in parts of the Phoenix metropolitan area, especially in the northern portion where a mud slide closes a road in Cave Creek. The washes in the Gila Bend area are full due to the torrential rains in the area.
- July 21-22: A late start of the monsoon brings heavy rain to the County. Sheet flooding in Queen Creek turns dirt roads to mud and causes a 1/4-mile-long, 12-foot-wide, 10-foot-deep fissure in the ground through a rural neighborhood. Several swift water rescues ware performed, including a 2.5-hour rescue operation in Queen Creek to save a motorist who had driven into a flood retention area.
- Sept. 7: Roads through Indian Bend Wash in Scottsdale are closed due to rainstorm runoff in the wash.
- Aug. 24: A rainstorm drops two inches of rain in parts of the northeastern Phoenix and north Scottsdale. Both bridged and unbridged crossings on Indian Bend Wash are closed. Two motorists attempt to drive across the wash on Indian Bend Road in Scottsdale. They become stranded, prompting a rescue by 40 members of the Scottsdale Fire Department. Each motorist is fined for the rescue per the state law that prohibits motorists from driving on a road that is barricaded due to flood hazards.
- Aug. 21: Some streets in northern Tempe are flooded, and the right-hand lanes of both eastbound and westbound U.S. 60 at Rural Road are closed due to heavy rain.
- July 25: Heavy rains create a sinkhole adjacent to an apartment building in Tempe, forcing residents to evacuate the community. Flood control basins in east Mesa are filled to capacity and pumping is required.
- Sept. 3: Very heavy rainfall across the far northern portion of the Phoenix metropolitan area results in rapid runoff and flooding. The Seven Springs stream gage indicates a sudden jump of the water level, from zero to 8.5 feet, in only 20 minutes. The Camp Creek ALERT system gage records a total of 3.11 inches of rain, with 2.01 inches in one hour. Bartlett Road is washed out and impassable, trapping about 400 motorists as they were attempting to leave Bartlett Lake. In Phoenix, the heaviest rain storm is reported at the East Fork of Cave Creek at 7th Avenue, with flooding of many streets in north Phoenix.
- Aug. 23: Flooding is reported on State Route 85.
- Aug. 9: Heavy rains from widespread thunderstorms cause flash flood waters to over-flow washes from New River east to the Seven Springs area and Camp Creek. Rain gage networks indicate that up to 4.5 inches of rain falls during the late afternoon and early evening. Two fatalities occurred during this storm: A pickup truck driver drowned while attempting to drive across a flooded road, and a seven-year-old girl being evacuated from a home along Camp Creek slipped from the grasp of the adult she was with and was swept away by a flooded wash. Heavy rains during the afternoon flood highways and roads in Queen Creek, while in Tonopah many roads are closed in the area due to rapid flooding.
- Aug. 2: One of the heaviest rainfall events of the 2005 season strikes the Phoenix area, where almost three inches of rain falls in many locations in the metropolitan area, causing roofs to collapse and streets to flood quickly. Nearly 120 residents of an apartment community in Phoenix are evacuated after 83 apartment units are damaged by floodwaters.
- July 30: Very heavy rainfall, about two inches per hour, causes the flooding of low spots and washes in Wickenburg, where the peak flow in Hartman Wash is 1,200 cubic feet per second.
- July 26: In Sun City, the occupants of a stranded vehicle in a flash flood are rescued at 128th Avenue and Galaxy Drive.
- Feb. 16: The governor declares a state of emergency in various counties due to 2005 winter storms and flooding. The declaration for Maricopa County only includes the town of Wickenburg. The total damage for the February flooding is estimated at $6.5 million.
- Feb. 12: Rains associated with a mid-winter storm system move slowly across central and southern Arizona. Rainfall intensity increases significantly during the evening of Feb. 11, and Flood Control District ALERT rain gages begin to report excessive rainfall exceeding 1.5 inches per hour during the early morning hours of Feb. 12. Rural roads in northern and northeastern Maricopa County become flooded by washes running heavy with the rain runoff. The Hassayampa River erodes its banks near Wickenburg, washing away two mobile homes and two vehicles. The Maricopa County Sheriff's Office rescues 21 individuals in 11 separate floodwater incidents during the weekend. Rock and mud slides along U.S. Highway 60 from Superior to Globe are reported by the afternoon of Feb. 12. Eventually, the Salt River and Verde River start to receive the runoff, with Granite Reef Diversion Dam spilling 35,345 cubic feet per second. Downstream, the river bottom road crossings on the Salt, Verde and Gila rivers are flooded. Tempe Town Lake, located in the Salt River channel, lowers its inflatable dams to allow for increased water flow. This storm system is the final significant 2004-2005 winter event in a season of very heavy rainfall. The Carefree-Cave Creek area reports a three-month total of 13.66 inches.
- Dec. 29: Heavy rains fall across a large portion of southern and central Arizona. The rapid runoff results in flooded washes.
- Aug. 15: Flash flooding is reported south of U.S. Highway 60 on Vulture Mine Road near Wickenburg. Three to four inches of rain fall in one hour.
- Oct. 10: Heavy rain falls across parts of northern Maricopa County and the rapid runoff results in flooded washes and streams. Storm totals are up to 1.30 inches at Skunk Creek near New River and 2.24 inches at Pinnacle Peak in north Scottsdale. Many vehicles become stuck in the deep water and some motorists have to be rescued.
- Sept. 4: Near Wickenburg, Sols Wash grows to about 150 feet wide, Flying E Wash is full and Vulture Mine Road is closed due to flooding. Flash flooding occurs at the entrance to the White Tank Mountain Regional Park near the intersection of Olive Avenue and Citrus Road in the western part of the Phoenix area. Two occupants of a vehicle on Olive Avenue are rescued by law enforcement after they became trapped in three feet of rushing water.
- Aug. 28: Locally heavy rainfall affects a large part of the Phoenix metropolitan area. The heaviest rain falls north of Sun City where one gage records approximately four inches. More than two inches falls at Antelope Creek near Wickenburg. Washes overflow and roads are flooded. Several swift-water rescues are performed and several homes are damaged by flooding.
- Aug. 14: At least 15 homes are flooded in Tolleson.
- Aug. 13: A flash flood in Sols Wash sweeps a vehicle downstream from Vulture Mine Road.
- Aug. 1: Thunderstorms with heavy rainfall of up to one inch per hour cause flash flooding of washes and streets in Wickenburg.
- March 7: Heavy rain over much of south-central Arizona leaves washes running and streets flooded or closed. More than two inches of rain falls in Wickenburg and two inches is recorded over much of the Phoenix area.
- Oct. 27: The second major storm in a week causes considerable flooding in both rural and urban areas. A trailer park in Aguila and another in Buckeye are evacuated, while homes in Peoria, Youngtown, Surprise and surrounding areas are flooded. One unofficial rain gage 15 miles east of Aguila registers 8.79 inches for the month and another gage in Aguila records 5.05 inches. The Department of Transportation estimates the damage to roads and bridges alone at $1 million. Dikes and ditches in agricultural areas sustain major damage in addition to crop losses. The Federal Emergency Management Agency (FEMA) declares a flood emergency for Maricopa County.
- Oct. 21: State Route 93 is closed north of Wickenburg due to high water. Sols Wash overflows and floods Coffinger Park as well as nearby homes. Vulture Mine Road is closed and trapped motorists are rescued. Floodwaters produce considerable damage to agriculture in northwestern Maricopa County. The roads around Aguila are closed for several hours. The governor declares a flood emergency for Maricopa County.
- Oct. 10: A strong storm system moves through the Phoenix area producing very heavy rainfall, resulting in street flooding and road closures. The Phoenix Fire Department responds to four swift-water rescues. Flooding is reported around Indian Bend Wash.
- Aug. 29: Very heavy rainfall, with estimated rates of an inch per hour, moves slowly across the County. Sols Wash in Wickenburg is flooded as well as other streams and washes in the northern part of the County.
- Aug. 17: One inch of rain falls in 15 minutes, causing a flash flood that fills washes near New River.
- June 20: About 2.5 inches of rain falls in just 90 minutes. In New River, a vehicle is swept downstream by heavy rainfall runoff.
- March 5-7: A series of storm systems move through Arizona during the three-day period, dropping as much as 3.5 inches of rain across north-central Maricopa County. Sky Harbor Airport records 2.77 inches and many areas of the city have more than two inches. Numerous motor-vehicle accidents are blamed on wet or flooded streets and intersections.
- Aug. 31: Rainfall exceeds one inch per 30 minutes in parts of the eastern Phoenix metropolitan area, resulting in street flooding.
- July 15: Showers and thunderstorms develop over a wide area between Wickenburg and Phoenix, with streets and roads flooded.
- July 14: A major storm hits most of the Phoenix metropolitan area with numerous reports of street flooding. At least six swift-water rescues are performed, including a dramatic rescue using a sheriff's department helicopter.
- March 5: A series of storms moves through Arizona over a three-day period and produces the third-wettest March on record in Phoenix, causing widespread street flooding.
- Oct. 30: Sheriff's deputies form a human chain to rescue a woman trapped in her car in a flooded wash on 14th Street south of the Carefree Highway in the northern Phoenix metro area.
- Sept. 5: Sheriff's deputies rescue at least one camper stranded by flash flood water at the campground at Apache Lake.
- Aug. 12: Very heavy rain causes considerable flash flooding around Wickenburg.
- March 28: Three members of a Boy Scout troop perish after their SUV is swept away after they try to drive across a flooded wash near Sunflower.
- Sept. 26: An average of three to five inches of rain falls from storms caused by Hurricane Nora, leading to flash flooding in portions of northwestern Maricopa County. Two earthen dams give way in Aguila, causing widespread flooding where approximately 40 people are evacuated from the town. Water flowing down the Sols Wash is so high that the Sols Wash bridge in Wickenburg is closed for more than two hours along with other highways in the vicinity. A total of 11.97 inches of rain falls in 24 hours on Harquahala Mountain, breaking the 24-hour record set at Workman Creek during the 1970 Labor Day storm.
- Sept. 25: Widespread flooding occurs in the town of Aguila, with many properties and roads are under six inches of water.
- Sept. 2: Many cross-streets are flooded along Thomas Road in Phoenix.
- Aug. 26: Water flowing through Indian Bend Wash rises to three feet. Automobiles become stranded in the wash at McCormick Parkway between Hayden Road and Scottsdale Road.
- Aug. 18: Indian Bend Wash floods quickly and forces the closure of two roads.
- Sept. 28: More than two inches of rain fall in Scottsdale, flooding streets and homes and filling Indian Bend Wash.
- Feb. 15: Floodwaters from the Hassayampa River near Wickenburg cause some property damage.
- Sept. 13: Extensive street flooding in Phoenix is caused by torrential rains.
- Sept. 4: More than 1.5 inches of rain falls in one hour in Litchfield Park, resulting in major street flooding.
- Sept. 2: Extensive street flooding is reported around the Phoenix area with water three to five feet deep in some freeway underpasses.
- Oct. 6: Heavy rain causes Indian Bend Wash to overflow onto city streets and wash over the bridges on Camelback and Indian School roads. A few motorists are rescued from their cars when they become stranded after trying to cross the flooded wash.
- Feb. 8-10: Flooding on the Hassayampa River forces 30 people to leave their homes.
- Jan. 8-20: An extremely intense El Niño causes heavy rainfall. A large, garbage landfill in Mesa and portions of the new Mill Avenue bridge that is under construction are washed away by the raging Salt River. The Gillespie Dam west of Phoenix is damaged as high water spreads throughout low-lying areas. One man drowns while trying to cross the Agua Fria River.
- July: A summer storm causes scattered flooding, particularly in east Mesa near the Central Arizona Project canal that is under construction.
- Sept. 28-Oct. 7: Tropical Storm Octave causes heavy rain over Arizona during a 10-day period. Southeastern Arizona is particularly hard hit, where at least 10,000 people are left temporarily homeless along with 14 fatalities and 975 injuries attributed to the flooding. Damage is estimated at $370 million. This massive storm brings floodwater north along the Santa Cruz and Gila rivers to Maricopa County, causing extensive flooding of streets and highways with some flooding of homes and businesses. One freeway underpass is filled with nine feet of water.
- January: Severe flooding on the Salt, Verde, Agua Fria and Hassayampa rivers, and along the Gila River below the confluence with the Salt River. The Salt River below Granite Reef Dam and the Agua Fria below Lake Pleasant are raging torrents, with a peak flow of 170,000 cubic feet per second. The greatest flood damage occurs along the Salt River in the greater Phoenix area. Eleven of the 13 bridges or crossings are destroyed or damaged. Approximately 600 homes to the west of Phoenix are damaged and others are destroyed, with 6,000 residents being evacuated. Damage is estimated at $63.7 million.
Between October 1977 and February 1980, seven regional floods occur and Phoenix is declared a disaster area three times. There are 18 fatalities and approximately $310 million in property damage.
- August: Tempe and Mesa streets flood due to heavy rainfall.
- November: Floodwaters virtually destroy the community of Allenville near Buckeye and cause heavy damage in Holly Acres on the Gila River and Hound Dog Acres on the Agua Fria River. The Salt River has a peak flow of 140,000 cubic feet per second. Damage estimated at $51.8 million.
- March: Phoenix receives federal disaster assistance funds after the heaviest flooding and largest floodwater flow down the Salt River since 1891. The Salt River has a peak flow of 122,000 cubic feet per second. Thousands of homes are damaged and more than 100 homes are destroyed. There are four fatalities as more than 7,000 people seek emergency shelter. Damage estimated at $33.1 million.
- Sept. 11: Hurricane Kathleen causes severe flooding. Mud and rock slides damage homes on Camelback Mountain.
- August: Excessive rain causes considerable flooding of streets and highways in the Phoenix area, with water up to eight feet deep at one of the underpasses of the Black Canyon Freeway (I-17). There is substantial flooding over much of Tempe and southeastern Phoenix.
- Oct. 17-21: Hurricane Joanne turns into a powerful tropical storm upon landfall, causing flooding, eight fatalities and more than $10 million in damage.
- June: Extensive damage due to flooding in downtown Phoenix, Paradise Valley and Scottsdale. Severe flooding occurs on Indian Bend Wash and the wash between Camelback and Mummy mountains. More than 800 homes are damaged or destroyed. Damage estimated at $10.5 million.
- Sept. 5-7: The precipitation from Tropical Storm Norma creates Arizona's deadliest storm to date. Known as the "Labor Day Storm of 1970," rainfall causes flooding that kills 23 people in the Phoenix area. Damage estimated at $5.8 million.
- Aug. 29: Widespread flooding occurs, especially in central Phoenix, due to remnants of Hurricane Katrina.
- Dec. 22, 1965 – Jan. 2, 1966: Heavy rains cause the first large flow of the Salt River through Phoenix since dams constructed on the Verde River in 1939 created the Horseshoe and Bartlett reservoirs. All roads crossing the Salt River in Tempe, Phoenix, Scottsdale and Mesa are washed out. All bridges across the Salt River are at least partially damaged, floodwaters encircle Sun Devil Stadium on the Arizona State University campus, a runway is closed at Sky Harbor Airport in Phoenix and Phoenix International Raceway is threatened by floodwaters. Damage estimated at $10 million.
- July: Flooding causes property damage in Phoenix and Wickenburg, and the Arizona Canal is breached.
- October: Floodwaters inundate homes in Phoenix and cause considerable damage to roads in Scottsdale.
- Aug. 16: Floodwaters from a severe storm breach the Grand Canal and cause flooding in Glendale and the Maryvale neighborhood of Phoenix. Damage estimated at $2.9 million.
- Sept. 26-28: The remains of Tropical Storm Claudia cause flooding, one fatality and $3 million in damage, mostly to agriculture near Casa Grande.
- August: The most severe storm since 1891 occurs in the Queen Creek area. Gilbert and Apache Junction are severely flooded. Damage estimated at $446,000 for property and $1.4 million for agriculture.
- Aug. 24-28: Flash floods cause damage in Goodyear and Avondale. Canals and ditches are extensively damaged, Luke Air Force Base and the Harquahala Valley see significant flooding, and Gila Bend is cut off from motor vehicle travel as bridges and roads are washed out. The total damages for this flood event exceed $750,000.
- March: Heavy flooding is recorded along the Verde River.
- Feb. 16: Floodwaters halt the construction of Bartlett Dam on the Verde River.
- Feb. 16: Water flows over the apron of Gillespie Dam. The Agua Fria River washes out sections of the bridge at Coldwater. Two bridge spans over the Hassayampa are washed away near Arlington.
- Sept. 20-25: The Verde and Salt rivers experience severe flooding.
- Aug. 21: Six inches of rain in two days floods 4,000 acres in the Phoenix area, including the Arizona state capitol building, totaling $240,000 in damage.
- Nov. 28: Flooding is reported throughout the Phoenix area: the Central Avenue bridge over the Salt River is closed, Cave Creek flows down Grand Avenue, Alhambra and the state fairgrounds site are under water, the Agua Fria River railroad bridge washes out and Paradise Valley is flooded.
- Jan. 19-22: Intense rain and melting mountain snow produces large river flows in central Arizona. There are four fatalities and $300,000 in damage. The Salt and Verde rivers experience severe flooding, with water flowing over the spillways of Roosevelt Dam.
- Jan. 30: At least four Phoenix-area canals suffer damage from runoff from Cave Creek, Queen Creek and other washes. The Hassayampa River overflows its banks.
- Nov. 27-30: Several severe to moderate floods occur, particularly in Phoenix and along the lower Gila River. The Arizona Diversion Dam disappears under 11 feet of water. The railroad bridge across the Salt River in Phoenix is damaged.
- Feb. 18-26: The maximum flood of record for Maricopa County occurs on the Verde, Salt and Gila rivers. The Salt River has an estimated 300,000 cubic feet per second water flow, expanding to nearly three miles wide in the Phoenix area and rising to 18 feet above the wooden Arizona Diversion Dam at the confluence with the Verde River. Adobe homes along the Salt River are demolished and the railroad bridge between Tempe and Phoenix is destroyed, leaving Phoenix without a rail connection for three months. Remarkably, no fatalities are recorded.
- Feb. 22: At Phoenix, the Salt River rises 17 feet in 15 hours. Heavy rains and melting snow cause the failure of Walnut Grove Dam on the Hassaympa River 30 miles north of Wickenburg, drowning 128 people and causing considerable property damage.
- Dec. 5: The Salt and Verde rivers rise very rapidly, and at Fort McDowell the Verde River overflows its banks.