Olivia then steadily intensified before becoming a Category 4 hurricane, and reaching its peak intensity with 1-minute sustained winds of around 145 mph (230 km/h), at 18:00 UTC on September 21.

Moisture from Olivia was pulled across the Western United States and Southwestern Canada by a strong southwesterly flow.

This resulted in several inches of rainfall, which caused damaging flash flooding and mudslides, namely in Utah.

The origins of Hurricane Olivia can be traced back to a weather report from the cargo ship, Port Latta Maru, roughly 400 miles (650 km) south-southwest of Acapulco, Mexico.

Olivia continued to rapidly intensify, reaching its peak intensity as a Category 4 hurricane at 18:00 UTC on September 21, with 1-minute sustained winds of around 145 mph (230 km/h).

[1] Olivia weakened over the next couple of days, while turning to the north-west along the western periphery of the upper-level high.

Around this time, moisture from the storm was being carried across the Western United States and Southwestern Canada, by a strong southwesterly flow.

[1] Olivia weakened into a tropical depression while located about 500 miles (805 km) southwest of San Diego, California.

The system was last noted as a dissipating surface low on September 25, while located roughly 250 miles (400 km) west-southwest of San Diego.

[2] A dam burst in the Sierra Madre Mountains, causing 6 inches (152.4 mm) of water to enter into Bishop Creek.

An additional 200 people were stranded at Kings Canyon National Park, after a 15-mile (25 km) stretch of California State Route 180 was washed out.

[7] Following the floods, California Governor Jerry Brown declared a state of emergency for the Big Pine area.

According to the California Farm Bureau Federation, up to $110 million (1982 USD) worth of almonds, beans, grapes, and melons could have been lost.

Officials ordered off-duty crews and volunteers to sandbag streams and the Jordan River, to prevent further flooding.

The Red Cross provided shovels, mops, disinfectant, cots, and cooking utensils to requested areas.

[22] Olivia was the wettest-tropical cyclone in Utah on record, dropping a peak precipitation amount of 7.41 inches (188.21 mm), in Cottonwood Weir.

[25] With 2.20 in (56 mm) of rain in Powell, Idaho, Olivia became the wettest tropical cyclone in state history at the time.