Hurricane Nolo Strengthens Near Hawaii As Flood Threat Continues

Hurricane Nolo was seen moving west away from Hawaii on Sunday, Sept. 27, after bringing heavy rain, strong winds and dangerous surf to the islands, while forecasters warned that flooding and mudslides could continue even as the storm pulls farther away. Nolo is expected to strengthen into a major hurricane as it moves over warmer water south of the island chain.

The immediate tropical storm and hurricane watches and warnings have been discontinued, but high wind warnings remain for parts of the Big Island and Maui County, where wind gusts could reach 75 mph. More than 12 inches of rain has already been reported on the Big Island, leaving steep areas vulnerable to additional flooding and mudslides.

Why the danger is not over

Nolo had remained nearly stationary for several hours Saturday before beginning to move west at about 9 mph. As it moves farther from the islands, the heaviest rain is expected to shift away, but saturated ground and steep terrain could keep the flood threat alive.

Parts of the Big Island could receive another 1 to 4 inches of rain, pushing storm totals in some areas as high as 20 inches. Parts of Maui could receive another 2 inches, with total rainfall reaching about 8 inches in some locations.

The National Hurricane Center has warned that flooding and mudslides can occur even beyond the areas that receive the heaviest rainfall. That means runoff and debris can affect communities farther downhill from where rain is falling.

Nolo could become a major hurricane

The storm is forecast to pass south of the Hawaiian Islands while moving over warmer ocean water during the next 24 hours. Those conditions are expected to help Nolo strengthen into a major hurricane on Sunday.

A major hurricane is a storm with sustained winds of at least 111 mph, placing it in Category 3 or higher on the Saffir-Simpson Hurricane Wind Scale.

The strengthening is expected to occur after Nolo’s closest impacts on the islands, but the storm can still produce dangerous conditions across Hawaii through wind, rain, surf and coastal flooding.

Strong winds and dangerous surf remain

The strongest wind threat is expected across parts of the Big Island and Maui County. Wind gusts could cause tree damage and power outages, while stronger winds are possible near mountain peaks and on the downwind sides of mountains across the island chain.

Large swells generated by the hurricane are also creating dangerous surf and rip currents. Parts of the Big Island could continue to face coastal flooding through the weekend.

The combination of heavy rainfall, strong winds and rough seas creates several separate hazards, meaning conditions can remain dangerous even as the center of the hurricane moves farther away.

A rare hurricane threat for the Big Island

Nolo’s passage is notable because major hurricanes have rarely come this close to the Big Island.

According to NOAA’s hurricane database, only one other major hurricane has tracked within 150 miles of the Big Island. Hurricane Dot passed south of the island in August 1959 before striking Kauai.

That makes Nolo the strongest hurricane impact on the Big Island in 67 years, according to Weather.com.

The storm is also the fourth tropical system to at least graze Hawaii this season with significant rain or wind impacts. Hurricane Lala struck in mid-August, followed by Tropical Storm Moke and Hurricane Lowell.

Hawaii is still recovering from earlier storms

The timing of Nolo is especially important because some areas of Hawaii were already dealing with the effects of earlier storms.

Hurricane Lala brought flooding, mudslides, and strong winds to the Big Island in August, while some locations had only recently regained power. Moke later brought additional rain after the ground had already become saturated.

Hurricane Lowell also affected the western islands with wind, rain and waves after reaching Category 5 strength at its peak before weakening ahead of its closest pass.

With Nolo now moving west, the immediate focus is shifting from the hurricane’s approach to the continuing effects of rainfall, flooding, wind and coastal conditions. Residents in affected areas should continue following local emergency officials and weather alerts as the storm moves away.