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National Weather Service Forecast Office
Tucson, Arizona
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Cyclone: Hurricane Joanne
Date it affected AZ: October 6-7, 1972
Affected Arizona as...: Tropical Storm (passed through western Pima County, dissipated over northern Arizona)
 
Even though she weakened rapidly after making landfall near Puerto Peñasco on October 6th, Joanne probably moved northeast into western Pima County as a minimal tropical storm with maximum sustained winds around 40 mph. She weakened to a depression near Ajo, but made it all the way to near Flagstaff before dissipating. Widespread heavy rains of 1 to 3 inches fell over southeast Arizona, with isolated mountain totals over 5 inches. The Nogales Highway Bridge over the Santa Cruz River was washed away, as were many secondary roads in and around Tucson. Water rescues were conducted in central Tucson as several major streets turned into rivers. Joanne set the stage for major river flooding later in the month (October 17-21) as a Gulf of Alaska storm transported more tropical moisture into the state. That second flood killed eight and did hundreds of millions of dollars in damage.
 
Image of Hurricance Joanne track. Close up image of Hurricane Joanne track
   
Image of rainfall produced by Hurricance Joanne across Mexico and the southwest United States
Image courtesy of Hydrometeorological Prediction Center (http://www.hpc.ncep.noaa.gov)