2018 Pacific hurricane season

Season overview

Few eastern and central Pacific seasons have come close to 2018. Against a 1981 to 2010 average of about 15 named storms, 8 hurricanes and 3 major hurricanes, the year produced 23 tropical storms, 13 hurricanes and 10 major hurricanes, and the tropical storm tally ranks among the highest in the basin's record. What set it apart most was sustained power: several hurricanes stayed strong for a week or more over open water, and Colorado State University's accumulated cyclone energy figure of 318.1, calculated from the National Hurricane Center's best track, is the highest of any Pacific hurricane season on record. The archive behind this map gives 318.5, a small difference that comes from computing the index from IBTrACS one-minute winds during each storm's tropical stage rather than from the best track directly.

The ocean and atmosphere were primed for it. El Niño-like conditions prevailed over much of the basin, sea surface temperatures ran above average from the North American coast far out across the Pacific, and vertical wind shear was lower than usual. A stronger than normal subtropical ridge kept storms in favorable easterly flow, and the subtropical jet retreated northward in September, easing shear near Hawaii just as a run of powerful hurricanes moved into the central Pacific. NOAA's May outlook had called for 14 to 20 named storms, 7 to 12 hurricanes and 3 to 7 major hurricanes, citing the chance of El Niño; the season landed at or beyond the top of each range.

The site's counts match the official National Hurricane Center totals for the year: 26 tropical cyclones, of which 23 became tropical storms. The three that did not were short-lived depressions, One-E in May, Nine-E in July and Nineteen-E in September. A further system south of Alaska around the start of September, which some analyses treated as a subtropical or tropical storm, never entered the official best track and does not appear here.

How the season unfolded

Tropical Depression One-E formed on 10 May, five days before the official start of the eastern Pacific season, and fell apart within a day under strong shear. June then produced five named storms, tying 1985 for the most in that month. Hurricane Aletta and Hurricane Bud both rapidly intensified to Category 4 within days of each other, the first time since 2010 that two June storms had reached that strength. Aletta's winds rose by 65 kt in 24 hours over waters near 30°C. Tropical Storm Carlotta, Tropical Storm Daniel, Tropical Storm Emilia and Hurricane Fabio followed before the end of the month.

July was comparatively quiet, but the last day of the month brought the depression that became Hurricane Hector, and August turned busy. For a time in early August four cyclones were active at once: Hector, Tropical Storm Kristy, Hurricane John and Tropical Storm Ileana, which was eventually absorbed into John's circulation off southwestern Mexico. Hurricane Lane formed on 15 August and was followed within two weeks by Hurricane Miriam and Hurricane Norman, both of which also crossed into the central Pacific.

September and early October kept up the pace. Hurricane Olivia formed on 1 September and eventually reached Hawaii, Tropical Storm Paul came and went at sea, and Tropical Depression Nineteen-E formed over the Gulf of California. In the last week of the month Hurricane Rosa developed south of Mexico, and on 29 September both Hurricane Sergio and Hurricane Walaka formed, the latter south of Hawaii. October closed the season's main phase with Tropical Storm Tara, Tropical Storm Vicente and Hurricane Willa, and Tropical Storm Xavier brought activity to an end off Manzanillo in early November, with the last tropical observation on 5 November.

The strongest storms

Three hurricanes reached Category 5, and all three peaked at 140 kt. Hurricane Lane got there first, early on 22 August south of Hawaii with a central pressure of 926 hPa, and the site ranks it as the season's strongest storm. Hurricane Walaka reached the same winds with a lower pressure of 921 hPa on 2 October after rapid intensification south of Hawaii, giving it the lowest pressure of the year. Hurricane Willa followed on 22 October off southwestern Mexico, peaking at 925 hPa after nearly two days of rapid strengthening. Three Category 5 hurricanes in one season tied the basin record previously reached in 1994 and 2002.

Behind them sat a deep bench of Category 4 hurricanes: Aletta and Bud in June, Hector, Norman and Olivia in late summer, and Rosa and Sergio at the end of September and start of October. Hector was the standout for endurance. It reached 135 kt on 6 August after crossing into the central Pacific, weakened and restrengthened more than once, and spent more consecutive days as a major hurricane than any other storm in the basin's record. Its tropical stage lasted from 31 July until after it crossed the International Date Line into the western Pacific in mid-August, making it the longest-tracked storm of the season in this archive.

Several of these storms showed repeated cycles of weakening and recovery. Norman peaked at 130 kt on 30 August, fell back and then regained Category 4 and later Category 3 strength as it crossed toward Hawaii. Sergio went through three eyewall replacement cycles on a long, looping track and took on annular characteristics before weakening over cooler water.

Landfalls and impacts

Mexico took the heaviest blows, and the deadliest storms were not always the strongest. Hurricane Willa weakened after its Category 5 peak but still made landfall near Palmito del Verde, Sinaloa, early on 24 October UTC as a Category 3 hurricane. River flooding and mudslides devastated Escuinapa, Rosario and Acaponeta and isolated communities in Sinaloa and Nayarit; more than 96,000 people lost power and over 100,000 were displaced. The National Hurricane Center counted four direct deaths, all in Nayarit, and estimated damage in Mexico of at least US$536 million; wider tallies put the death toll at nine and damage at about 16.2 billion pesos, roughly US$825 million in 2018 dollars.

Tropical Depression Nineteen-E, the first known tropical cyclone to form over the Gulf of California, never reached tropical storm strength but brought torrential rain to northwestern Mexico on 19 and 20 September. The National Hurricane Center attributes eight direct deaths to it in Sinaloa and Chihuahua, plus two indirect deaths by electrocution in Culiacán. Sinaloa authorities estimated that as many as 300,000 homes were affected by flooding, and agricultural losses in the state were put at about 800 million pesos, roughly US$41 million. A month later, Tropical Storm Vicente's rain bands caused flooding and landslides in Oaxaca that killed 11 people, according to media reports cited by NHC, before the weakening system came ashore as a depression in Michoacán.

Other Mexican landfalls were weaker. Hurricane Bud rapidly lost strength and reached Baja California Sur near San José del Cabo as a 40 kt tropical storm on 15 June, with only minor rain and flooding impacts reported. Tropical Storm Ileana skirted the southwestern coast in August, and at least four deaths in Guerrero were attributed to it. Hurricane Rosa came ashore on the Baja California peninsula as a depression on 2 October, and Hurricane Sergio crossed Baja California Sur as a tropical storm on 12 October before a final landfall in Sonora. Moisture from Rosa and Sergio fed flooding rains across the southwestern United States, and Rosa's remnants caused about US$50 million in damage there.

Hawaii had an unusually eventful year. Hurricane Lane never made landfall but slowed as it turned north near the islands, and a gauge at Kahuna Falls on the Island of Hawaii recorded 58.00 inches of rain, a state record for a tropical cyclone and second only to Hurricane Harvey's total in United States history. Flooding hit more than 100 structures on the Island of Hawaii, wind-driven wildfires burned about 2,000 acres in western Maui, and a man drowned in a swollen stream on Kauai, the storm's one direct death; total losses exceeded US$250 million in 2018 dollars. Weeks later, Hurricane Olivia made the first recorded tropical cyclone landfalls on Maui and Lanai as a 40 kt tropical storm on 12 September, causing flash flooding, landslides and power outages but no reported casualties. Earlier, Hurricane Hector's passage south of the islands in August sent surf of 10 to 20 feet onto exposed shores without significant damage.

Hurricane Walaka's effects fell on remote territory. Its eye crossed the Northwestern Hawaiian Islands near French Frigate Shoals as a 110 kt hurricane on 4 October, and its surge and waves almost completely removed East Island, an important nesting site for threatened green sea turtles in an atoll that also hosts endangered Hawaiian monk seals. Researchers later found significant damage to coral reefs across the Papahānaumokuākea Marine National Monument. No casualties were reported.

Names and other records

Walaka was the only storm named in the central Pacific in 2018, and its name was the last on the fourth of the region's rotating lists, completing a cycle that began with the first name on the first list in 1982. In the eastern Pacific the season used every name on its list through Xavier, with Vicente appearing for the first time. No names were retired, and the list returned in 2024.