Hurricane Joanne (1972)

Hurricane Joanne

Category 2 hurricane (SSHWS/NWS)
Hurricane Joanne late on October 2
Formed	September 30, 1972
Dissipated	October 7, 1972
Highest winds	1-minute sustained: 100 mph (155 km/h)
Lowest pressure	971 mbar (hPa); 28.67 inHg
Fatalities	1
Areas affected	Baja California, California, Arizona, New Mexico
Part of the 1972 Pacific hurricane season

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 (SSHWS), October 2. Joanne then slowed down 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.

On September 26, ship reports and satellite imagery indicated an area of squally weather about 300 mi (485 km) 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 45 mph (70 km/h). A Hurricane Hunter aircraft investigated the growing storm on October 1 and estimated maximum sustained winds of 75 mph (120 km/h), making Joanne a Category 1 hurricane. However, very few ships reported winds greater than 30 mph (50 km/h) 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 100 mph (160 km/h) while turning towards the northwest.

On October 4, Joanne began to recurve, and developed winds of 90 mph (145 km/h). Later that day, the Eastern Pacific Hurricane Center (EPHC) 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.