On Sunday evening, Douglas was sitting just northeast of Oahu as a hurricane with sustained winds of 85 mph.
“Douglas will pass dangerously close to Oahu and Kauai tonight, producing a triple threat of hazards, including but not limited to damaging winds, flooding rainfall, and dangerously high surf, especially along east facing shores,” wrote the Central Pacific Hurricane Center (CPHC) in its Sunday evening advisory Hawaii time.
As of 5 p.m. Hawaii time, Douglas was about 60 miles northeast of Honolulu and 90 miles northwest of Maui. No hurricane on record has ever passed along Douglas’ current course.
Hurricane warnings are up for Oahu and Kauai. However, the hurricane warning for Maui was dropped as was the tropical storm warning for the Big Island, as the storm had passed to their west and north.
On Sunday, the storm’s track veered just far enough to the north to spare Maui and the Big Island from its worst effects. This northward jog could also somewhat reduce the storm’s wrath on Oahu and Kauai but the Hurricane Center urged vigilance.
“It remains important that you do not focus on the exact forecast track of Douglas,” it wrote Sunday evening. “Due to Douglas’ angle of approach to the islands, any wobble in the track could lead to drastic differences in where the worst weather occurs. Even if the center remains offshore, severe impacts could extend well from the center and be realized over Oahu and Kauai.”
In addition to its shift to the north, the storm had weakened slightly Sunday, with peak winds down to 85 mph, but remained a Category 1 hurricane. Some additional slow weakening is predicted as the storm continues westward, the Hurricane Center said.
Even if the storm weakens more, Douglas could inflict “quite a lot of damage,” Chris Brenchley, director of the CPHC, said.
As is the case with Tropical Storm Hanna in Texas, Hurricane Douglas is striking a state that has been seeing a growing number of coronavirus cases. Saturday was the third day in a row with record-high covid-19 cases, according to the Honolulu-Star Advertiser. State labs have suspended testing during the storm, with services expected to return early week.
Honolulu, located on Oahu, is opening 13 evacuation centers, the paper reported. City officials have taken covid-19 precautions, such as providing for social distancing. The Hawaii Convention Center is among locations being used. It can hold up to 1,600 people with covid-19 precautions in place.
‘Life-threatening’ winds, waves and flooding rains
Douglas is a relatively small storm, but its expected proximity to the islands means they all will be affected. As of Sunday evening, hurricane-force winds extended up to 40 miles from the center, and tropical-storm-force winds were found as far as 115 miles from the center.
“A combination of higher than predicted water levels, storm surge, and warning-level surf will lead to significant beach erosion,” the National Weather Service Honolulu wrote.
Large waves have been crashing into the northern shores of the island chain in recent days. Waves will build as the storm transits the island area, along with deadly rip currents. As the center passes, NWS is warning of a damaging storm surge up to three feet above the normal high-tide level. The greatest storm-surge risk should tend to be focused on the northeast shores of Oahu and the eastern half of Kauai.
Onshore in Oahu, strong winds are anticipated with the worst wind impacts on the northern and leeward parts of the island.
Widespread wind damage is possible in areas that are closer to the storm center. The mountainous terrain could create localized areas of enhanced winds because of wind-tunnel-like effects of mountain passes.
While the storm will pass relatively quickly, rainfall totals of 3 to 6 inches are a good bet in the hardest-hit spots, and some locations may reach 10 inches or more. Torrential rain is likely to lead to flash flooding, as well as flooded rivers and tributaries, especially in northern Kauai.
Hawaii’s location near cooler sea-surface temperatures has historically protected it from anything but the rare hurricane strike. There have been only two hurricane landfalls there in modern times; Category 1 Hurricane Dot in 1959 and Category 4 Iniki, which caused widespread damage on Kauai in 1992.
Correction: This article originally stated that at 5 p.m. Hawaii time on Sunday, Douglas was positioned 90 miles northwest of Kauai, whereas it should have said Maui.