Hurricane Joanne was one of four tropical cyclones to bring gale-force winds to the Southwestern United States in the 20th century. A tropical depression developed on September 30, 1972. It then moved west northwest and intensified into a hurricane on October 1. Hurricane Joanne peaked as a Category 2 hurricane, as measured by the modern Saffir-Simpson hurricane wind scale, October 2. Joanne then slowed and began to re-curve. Joanne made landfall along the northern portion of the Baja California Peninsula as a tropical storm. The tropical storm moved inland over Sonora on October 6 and was believed to have survived into Arizona as a tropical storm. In Arizona, many roads were closed and some water rescues had to be performed due to a prolonged period of heavy rains. One person was reportedly killed while another was electrocuted. A few weeks after the hurricane, Arizona would sustain additional flooding and eight additional deaths.
Meteorological history
On September 26, ship reports and satellite imagery indicated an area of squally weather about south of Guatemala. During September 27 and September 28, the disturbance moved westward. On September 29, the disturbance developed a closed low-level atmospheric circulation. The following day, the system was designated as a tropical storm after a ship reported winds of. A Hurricane Hunter aircraft investigated the growing storm on October 1 and estimated maximum sustained winds of, making Joanne a Category 1 hurricane. However, very few ships reported winds greater than at that time. On October 2, the Eastern Pacific Hurricane Database, noted that the hurricane had intensified into a Category 2 system, with winds peaking at while turning towards the northwest. On October 4, Joanne began to recurve, and developed winds of. Later that day, the Eastern Pacific Hurricane Center downgraded Joanne into a tropical storm as the system weakened. Accelerating north and later northeast, Joanne made landfall near Laguna Chapala on Baja California while a tropical storm late on October 5. Although records from the EPHC suggest that the tropical storm moved inland over Sonora on October 6, it is likely that Joanne moved northeast into western Pima County as a minimal tropical storm. Tropical Storm Joanne weakened to a depression near Ajo, but made it all the way to Flagstaff before finally dissipating.
Impact
The initial disturbance to Joanne brought squally weather to Guatemala. Upon making landfall in Mexico, the highest rainfall total was in San Felipe/Mexicali. Puerto Penasco recorded winds of. Further north, Joanne caused heavy surf in California, and brought tropical storm-force winds to the state. Prior to landfall, flash flood watches were issued for the southern portion of the state. Heavy rainfall was reported throughout Arizona. Over was measured at the Mogollon Rim. Many areas of the state received between of rainfall, with isolated locations receiving over. In Phoenix, of rain fell in a four-hour period, compared to the October average of. The Nogales Highway Bridge over the Santa Cruz River was washed away by the flooding. Some secondary roads near Tucson were flooded. Numerous water rescues were conducted in central Tucson since several major streets turned into rivers. Severe flooding was recorded in Clifton, Duncan, and Safford. An official in Maricopa Countylost track on the exact number of roads that were closed because of the hurricane. Many neighborhoods in northern Phoenix were evacuated early on October 7 when a canal overflowed its banks due to prolonged rainfall. Downtown, a young man was electrocuted when he tried to remove a downed power line that was on his car. One person was also killed in the city. Following the storm, heavy rain from Joanne set the stage for additional flooding in mid-to late October from a Gulf of Alaskaextratropical cyclone that brought more moisture to the area, causing $10 million in property damage and eight deaths. Further west in New Mexico, the hurricane produced of precipitation. Hurricane Joanne is one of only four known Pacific hurricanes to bring gale-force winds to the Continental United States, and was the first since the 1939 California tropical storm. According to the National Weather Service, it was the first time in recorded history that a tropical cyclone had brought gale-force winds to Arizona.
