GroundTruth

- GroundTruth
  
  For more than 20 years Earth Networks has operated the world’s largest and most comprehensive weather observation, lightning detection, and climate networks.
  
  We are now leveraging our big data smarts to deliver on the promise of IoT. By integrating our hyper-local weather data with Smart Home connected devices we are delievering predictive energy efficiency insight to homeowners and Utility companies.
- GroundTruth
- WeatherBug
  - Consumer
  - Corporate
- WeatherBug
  - Consumer
  - Corporate

On this day in 1972, Tropical Storm Joanne brought significant flooding to southern Arizona.

The disturbance which would eventually become Joanne was first identified by ships 300 miles west of Guatemala on September 26, 1972, and the system brought stormy weather to Guatemala as it moved to the west over the next few days.

On September 29, the system was observed to have a surface circulation and was producing sustained winds to 45 mph. This meets the requirements of a tropical storm, and the system was named Joanne as it continued to strengthen.

A few days later, on October 1, NOAA Hurricane Hunter aircraft investigating Joanne observed 75 mph winds within the storm, making Joanne a Category 1 hurricane on the Saffir Simpson scale. Joanne reached maximum intensity on October 2, 1972, with sustained winds estimated at around 100 mph.

After reaching peak intensity, Joanne reached a less favorable environment and gradually weakened while turning to the northeast. The storm weakened into a Tropical Storm on October 4, and made landfall near Laguna Chapala, Mexico on October 5.

Later that same day, the center of Joanne made landfall in Sonora, Mexico, and throughout the course of this passage the storm was producing winds up to 50 mph and heavy rainfall. The maximum rainfall that fell from Joanne in Mexico was 9.45 inches near Mexicali, with widespread rainfall totals of 1 to 4 inches across Baja California and Sonora.

Joanne held itself together quite well as it made the short journey across Sonora, and when it entered southern Arizona it was still a Tropical Storm. It is one of only four tropical cyclones to bring gale force winds to the southwestern U.S. in the twentieth century. Joanne continued to slowly move north, becoming a tropical depression south of Gila Bend before dissipating all the way north in the Flagstaff area.

As is often the case with landfalling tropical systems, wind was not the issue but rather water. Widespread rainfall totals of 1 to 3 inches were observed in Arizona and western New Mexico as Joanne moved through, causing significant flooding particularly near Tucson and Phoenix.

Numerous road closures occurred in and around Tucson due to flooding, with the Nogales Highway Bridge over the Santa Cruz River south of Tucson collapsing entirely. Water rescues had to be performed in Tucson as local roads turned to rivers on October 6 while Joanne made its closest approach. On the morning of October 7, 1972, neighborhoods in northern Phoenix were evacuated as a local canal overtopped its banks causing flooding in the area. One death was reported attributed to Joanne in Arizona, with another severe injury being caused by a downed powerline on a car in downtown Phoenix.

While Joanne was a damaging storm across the region, it was quickly overshadowed by a non-tropical system which brought even more rainfall, worse flooding damage, and eight deaths to Arizona starting on October 17, 1972. The name Joanne was used again in 1976, after which tropical cyclone naming conventions changed and the name was discontinued.

Credit: Wikipedia.org, NOAA, NWS

Story Image: This ESSA 9 weather satellite image of Hurricane Joanne was taken on October 2, 1972 at 2233 UTC. (Credit: NOAA)

- Live Radar
- - Weather Details
- Forecast
  
  }
- Featured Videos
- Air Quality

On This Day in 1972: Tropical Storm Joanne Floods Arizona