Hurricane Nora was the first hurricane to cause a significant danger to the Continental United States since Kathleen in 1976.
Part of a tropical wave that contributed to the formation of Hurricane Erika in the Atlantic moved into the Pacific and organized into Tropical Depression 16-E on September 16 and Tropical Storm Nora that same day. Nora became a hurricane in a favorable environment September 18 while moving northwest. Its motion then stalled over an upwelling of cooler water that weakened it.
On September 20, Nora again started moving. It reached its peak intensity of 115 knots and 950 mb On September 21 and 22 it moved over the wake of Hurricane Linda. This weakened the storm pack down to a Category 1.
During this time, a trough developed that turned Nora to the northeast. This carried Nora over a favorable environment and towards Baja California. After restrengthening slightly, Nora made landfall as a Category 1 hurricane near Punta Eugenia and again south of San Fernando, both times as a hurricane.
Nora stayed a tropical storm as it moved into the United States. Yuma reported sustained gale-force winds. Rains were heavy, sometimes exceeding the "annual" rainfall for the area. Nora weakened to a depression while over California, and it dissipated September 26.
Nora killed two people in Mexico. One was killed by a downed power line in Mexicali, and the other was a scuba diving in underwater currents. No one in the United States was directly killed by Nora. However, the California Highway Patrol attributed several traffic accident deaths to the weather.
There was extensive damage to areas hit by Nora. Waves ruined dozens of homes. Roughly 350 to 400 people were left homeless in San Felipe, and winds uprooted trees and peeled roofs from homes in Puerto Peñasco.
In the United States, thousands were left without power in California and Arizona, and 16 telephone poles were downed in Seeley. Streets flooded in San Diego, Indio, El Centro, and Palm Springs. A remnant circulation continued aloft, and damaged trees and three homes in Utah. Total damages were "several hundred million dollars", as well as 40 million dollars to lemon trees.
Nora crossed an area of abnormally warm water near the west coast of the Baja California Peninsula. It restrengthened slightly before making its first landfall near Bahía Tortugas, Baja California Sur. When Nora was inland, the area of the storm located in the Gulf of California began to reintensify. Hurricane Nora then made a second landfall about 60 miles (95 km) south-southeast of San Fernando, Baja California.
At landfall, a trough was accelerating Nora northwards, causing it to reach a forward speed of 30 mph (50 km/h). Late on September 25 (UTC), still a tropical storm, it entered the continental United States at the California-Arizona state line. Nora began to weaken rapidly, and was downgraded to a tropical depression three hours later, while located between Blythe and Needles, California. Nora reached Arizona while still tropical, becoming the third known system to do so. Nora degenerated over land, and the low-level center moved towards the north-northeast. A remnant circulation aloft persisted, however, and was likely responsible for a period of near hurricane-force winds observed at the NWS Cedar City, Utah Doppler weather radar. The remnants gradually became more diffuse over the following two days while moving generally northeastward, through portions of Utah, Colorado, Idaho and Wyoming.
On September 24, Arizona Governor Jane Dee Hull activated an emergency response center to prepare the state's response to the flash flooding the storm would cause on the dry desert floor, and Yuma residents began to fill approximately 55,000 sandbags to contain the possible flooding. Hull also activated the state's National Guard, and sent drinking water and electric generators to Yuma. Farther inland, the National Weather Service issued flash flood watches for western Arizona, southeastern California, southwestern Colorado, southern Nevada and southern Utah on September 26.
In the United States, there were no direct deaths blamed on the hurricane. However, the California Highway Patrol attributed three or four traffic fatalities in southern California to the weather.