Hurricane Heather was one of the worst tropical cyclones to affect Arizona on record. The sixteenth tropical cyclone, eighth named storm, and fourth hurricane of the 1977 Pacific hurricane season, it began as a tropical disturbance off the west coast of Mexico on October 3. The next day, October 4, it developed into a tropical depression and then turned to the northwest. It was soon upgraded to Tropical Storm Heather. On October 5, Heather became a hurricane, and later that day its winds peaked at . Heather began to turn north-northwest around this time. By October 6, it was re-designated a tropical storm. Moving north, Heather continued to weaken over cooler waters, and on October 7, the final advisory was issued, downgrading Heather to a tropical depression.
Heather's remnants later brought heavy rains to southeast Arizona and far northern parts of Sonora from October 6–10, causing severe flooding. Rain totals as high as were recorded in unspecified areas in this region, and the city of Nogales in Arizona officially recorded of rain from the storm. The normally dry Santa Cruz River flooded several cities and towns along its path, reaching up to a 100-year flood stage near Nogales. Hundreds of people were driven from their homes due to flooding from Heather. Overall, the storm caused $15 million (1977 USD) in damage, primarily to agriculture, but caused no injuries or fatalities.
Meteorological history
Heather began as a tropical disturbance, roughly south-southwest of Manzanillo, at 18:00 UTC on October 3. Moving west-northwest at about , the disturbance intensified over sea surface temperatures (SSTs) of , and was upgraded to Tropical Depression Sixteen at 00:00 UTC on October 4. The depression turned to the northwest, and six hours later was upgraded to Tropical Storm Heather. Heather continued to intensify, and by 06:00 UTC on October 5, Heather was upgraded to a hurricane while 70 miles west of Socorro Island; the storm brought winds to the island at this time.
At 12:00 UTC on October 5, Heather reached peak winds of , while about west-northwest of Socorro Island. A NOAA reconnaissance aircraft estimated a sea-level pressure of at 21:00 UTC, the lowest recorded in relation to the storm. After this point, Heather began to weaken after moving north-northwest over colder SSTs. Heather fell to tropical storm status late on October 6, while about west of Isla Magdalena. Heather continued to weaken after turning north over waters as cool as , and satellite imagery showed the storm's upper and lower circulations separating by about . The final advisory on Heather was issued at 06:00 UTC on October 7, downgrading Heather to a tropical depression that was rapidly dissipating. Heather's remnants collided with a cold front on October 8 or 9, which became nearly stationary south of Nogales around this time for 24–36 hours, before weakening and moving east on October 10.
Impact
Total damage from the storm was at least $15 million, with approximately $9 million of that coming in the Tucson, Arizona area; the city of Tucson itself lost $2.7 million, with about $1 million being lost at a sewage treatment plant. About $9 million of the damage was agriculture-related; $4.7 million of that came in the Tucson area, and an additional $3.2 million came in Santa Cruz County in Arizona. Another $4 million in damage was related to transportation; at least $1 million came from the Tucson area, where four roads crossing the dry riverbed of the Santa Cruz River outside city limits and another four roads crossing the Santa Cruz within city limits were damaged. The other $2 million was in damage to businesses, residential areas, and utilities. No injuries or fatalities were reported as a result of the storm. At least 90 homes flooded, mostly near Nogales, Arizona.