Hurricane Olivia (1975)

Hurricane Olivia

Category 3 major hurricane (SSHWS/NWS)
Hurricane Olivia approaching landfall on October 24 at 2215 UTC
Formed	October 22, 1976
Dissipated	October 25, 1976
Highest winds	1-minute sustained: 115 mph (185 km/h)
Fatalities	30 direct
Damage	$20 million (1975 USD)
Areas affected	Mexico
Part of the 1975 Pacific hurricane season

Hurricane Olivia was considered the worst hurricane to hit Mazatlán, Sinaloa since 1943, in addition to being the strongest landfalling and costliest hurricane of the 1975 Pacific hurricane season. Olivia formed on October 22 to the south of Mexico, quickly intensifying into a tropical storm. The storm moved northwestward initially, followed by a northeast turn. On October 23, Olivia attained hurricane status, and the next day reached Category 3 intensity on the Saffir-Simpson scale just before moving ashore Mazatlán in northwest Mexico. Olivia destroyed 7,000 houses in the region, leaving 30,000 people homeless, and damage totaled $20 million (1975 USD, $89 million 2017 USD). The hurricane killed 30 people, 20 of them from drowning in shrimp boats.

The origins of Olivia were from an extended area of convection, or thunderstorm activity, that persisted southwest of Mexico in late October. Following the development of a circulation, the system formed into a tropical depression early on October 22 about 430 mi (690 km) southwest of Manzanillo, Colima. The depression quickly intensified into Tropical Storm Olivia as it tracked northwestward, although further strengthening was slowed. The circulation became much better defined on October 23 and after Olivia turned northeastward, it attained hurricane status that evening.

After reaching hurricane status, Olivia accelerated to the north-northeast. Several ships crossed its path, encountering strong winds and rough waves. On October 24, a Hurricane Hunters flight observed an elliptical eye and winds of 91 mph (146 km/h). Further intensification occurred, and around 0500 UTC on October 25 Olivia made landfall on Mazatlán, Sinaloa with peak winds of 115 mph (185 km/h) and gusts to 140 mph (230 km/h); this made Olivia a major hurricane, or a Category 3 on the Saffir-Simpson scale. It quickly dissipated after moving ashore.