Floods and Flash Floods

Flooding is a regular occurrence in the Tucson area and can occur during either of our two primary rainy seasons – the monsoon season (which can be further impacted by remnants of Pacific hurricanes) and our winter rains. Flooding can make roads impassable, can create dangerous conditions in and around usually dry washes, and can flood homes and businesses within the City. There are many incidents of flooding that have been recorded in the Tucson area, too many to describe here. However, here are some examples of relatively recent and large scale flooding events that have occurred in and around Tucson (be sure to visit Ready.gov's flood page for more information on flood preparedness):

During August and September of 1983, nearly seven inches of rain fell, saturating the soil around the Tucson metropolitan area. These conditions were exacerbated when a surge of moisture from Tropical Storm Octave, which was located off the central Baja California coast, moved northeast across the area. The result over a four-day period was torrential rains ranging from five to nine inches, causing flooding in Tucson and southeast Arizona. Bridges in the area, including all spanning the Santa Cruz River except one, were damaged or partially washed away. Additional damage occurred along the other watercourses throughout the area. Several buildings fell into Rillito Creek due to bank erosion and extensive damage occurred to agriculture in Marana. Cost estimates (using 1984 dollars) to repair and mitigate flood damage were estimated at $105.7 million. Four deaths in Eastern Pima County were attributed to the flood.

In late December 1992 - early January 1993, a series of winter storms produced record breaking precipitation amounts and severe weather across much of Arizona. Heavy rains combined with melting snowpack caused heavy flooding of both local washes and regional rivers within Pima County. Nearly every community and city within the county was impacted by the storms at some level. Most of the heavy damage was associated with the Gila, San Pedro, and Santa Cruz Rivers. The total public and private damages from the 1993 floods were estimated to exceed $12 million in Pima County alone. 19 The flooding prompted a federal disaster declaration for almost the entire state.

On August 14, 2005 and August 23, 2005 intense heavy rains caused significant damage to public infrastructure throughout Pima County. The severe runoff resulted in damages to numerous roads, traffic lights, water well fields, and berms, crossings, and police vehicles. After over an inch of rain fell across a large portion of the Tucson Metro Area, some locations with more than two inches, several roads became flooded, closed, and impassable. In addition to all the flooded roadways, several trailer homes located in the southern portion of the Tucson Metro Area, were flooded and surrounded by rising water. Rescue teams evacuated several people from these homes. Brawley wash was out of its banks and flooding roadways causing them to be impassable. Over $260,000 in damages were estimated.

In late July and early August 2006, several areas of the state were struck by severe storms and flooding during the period of July 25 to August 4, 2006. Tropical moisture poured into Southeast Arizona, saturating the ground at most locations. As rainfall continued, additional runoff quickly filled rivers and washes, exceeding bank full capacities and flooding homes and businesses as well as nearby roads. Some roadways were washed away due to the strong flood waters. Lots of flash flooding occurred throughout the Tucson Metro Area due to saturated grounds and extremely heavy rainfall. Numerous roads were closed due to flooding throughout the entire Metro Area for many hours. Additionally, there were numerous swift water rescues and car stranded in flooded roadways. It was estimated that nearly 100 vehicles were flooded. Several rivers running through the Tucson Metro Area flooded on July 31, 2006. The Rillito River flooded with water over the cement banks near Dodge Boulevard. Additionally, the Rillito River was over bank full just east of the Swan Road Bridge. River Road near La Cholla Road was flooding from the Rillito River. Sabino Creek was out of its banks and houses were flooded near Sabino Canyon and Bear Canyon. Below is a listing of some of the damage, but not all, caused by the flooding and an estimate for the cost of repairs:

Sabino Canyon Recreation area road and facility damaged, $100,000

Forty homes and businesses flooded, $1,200,000

One home destroyed due to flooding, $150,000

Water main broke near the Mt. Lemmon highway, $20,000

Catalina Highway road washed away, $50,000

Agricultural irrigation system damaged, $500,000

Cement plant flooded, $400,000

Gravel pit flooded, $30,000

General infrastructure damage, $500,000.

The flooding prompted a federal disaster declaration for Gila, Graham, Greenlee, Pima, and Pinal Counties. Total disaster expenditures exceeded $13.6 million.

On February 19, 2008 a state of emergency was declared for Pima County for flooding and damages due to 8.5 inches of precipitation that fell in and around Mt. Lemmon within Pima County in less than a 24-hour period. Damages to roads left residents stranded in their homes, limited access to food and medical assistance and damaged potable water supply lines, which impacted transmission and distribution of potable water to homes. The rainfall and snowmelt created conditions that threatened the health and safety of residents and exceeded the capabilities of Pima County. Several people in Tucson needed to be rescued from flowing washes. Damages were estimated to exceed $770,000.

In January 2010, sixteen hikers were trapped on Sabino Canyon Trail at approximately 11 AM on January 21st after the stream rose above its banks, covering low water crossings. Several washes flowed out of their banks, resulting in barricaded roadways near Saguaro National Park East and West, including East Tucson and Avra Valley. A motorist was trapped in the Canada del Oro Wash near Rancho del Lago at approximately 7 AM on January 22nd requiring a swift water rescue. Storm-wide damages were estimated at $300,000. A presidential disaster was declared for several counties and Indian tribes in the state including Pima County.

In July 2010, torrential rainfall across portions of eastern Pima County resulted in numerous reports of flash flooding in the Tucson metro area. Flash flooding was observed on Tanque Verde Creek with a peak depth of 11.69 feet at Tanque Verde Guest Ranch. Approximately 30 homes on Barbary Coast Road, Gold Dust Road, and Kitt Carson were flooded. Numerous swift water rescues were performed in the Tucson metro area, near the county fairgrounds, in the Recon Valley area, and on the Old Spanish Trail in the Hilton Head Ranch area. Damages were estimated to exceed $500,000.