Hurricane Walaka was a Category 5 hurricane that brought high surf and a powerful storm surge to the Hawaiian Islands. Walaka was the nineteenth named storm, twelfth hurricane, eighth major hurricane, and second Category 5 hurricane of the 2018 Pacific hurricane season.
The tropical cyclone originated from an area of low pressure that formed around south-southeast of Hawaii on September 24. The system tracked westward and moved into the Central Pacific Basin about a day later. The disturbance continued westward over the next few days, organizing into a tropical depression on September 29. Later that day, the system strengthened into a tropical storm, receiving the name Walaka. The storm then rapidly intensified, becoming a hurricane on September 30 and a major hurricane by October 1. The cyclone took on a more northward track under the influence of a low-pressure system located to the north. Walaka peaked as a Category 5 hurricane, with winds of and a pressure of , early on October 2. An eyewall replacement cycle caused the hurricane to weaken, though it remained a major hurricane for the next couple of days. Afterward, less favorable conditions caused a steady weakening of the hurricane, and Walaka became extratropical on October 6, well to the north of the Hawaiian Islands. The storm's remnants accelerated northeastward, before dissipating on October 7.
Although the hurricane did not hit any major landmasses, it passed very close to the unpopulated Johnston Atoll as a strong Category 4 hurricane, where a hurricane warning was issued in advance of the storm. Four scientists there intended to ride out the storm on the island, but were evacuated before the storm hit. Walaka neared the far Northwestern Hawaiian Islands, but weakened considerably as it did so. East Island in the French Frigate Shoals suffered a direct hit and was completely destroyed. The storm caused significant damage to the nesting grounds for multiple endangered species; coral reefs in the region suffered considerable damage, displacing the local fish population. Several dozen people had to be rescued off the southern shore of Oahu as the storm brought high surf to the main Hawaiian Islands.
Meteorological history
On September 22, 2018, the National Hurricane Center (NHC) forecast that a low-pressure area would form around 130–140° west. Two days later, a troughan elongated region of low atmospheric pressure formed around south-southeast of Hilo, Hawaii. The disturbance entered the Central Pacific Basin on September 26 as a mixture of low-level clouds and larger cumulus clouds. A subtropical ridge located north of the Hawaiian Islands caused the system to track westward over the next few days. A surface low formed by 12:00 UTC on September 27 as the system was located southeast of Hilo. The system became Tropical Depression One-C around 12:00 UTC on September 29 while it was around south of Honolulu, Hawaii. Convection or thunderstorm activity formed near the system's low-level circulation center, and a banding featuresignificantly elongated, curved bands of rain clouds became established over the southern and eastern portions of the depression. Six hours later, the system strengthened into a tropical storm, receiving the name Walaka from the Central Pacific Hurricane Center (CPHC).