HONOLULU --Hawaii residents prepared for what could be the first hurricane to hit the state in more than 20 years as weather officials said Wednesday that an approaching storm appears to have strengthened and will likely maintain its speed as it heads toward the islands.
Hurricane Iselle loomed about 600 miles east of Hilo, spinning at about 85 mph, forecasters said. It had been expected to weaken significantly before reaching the Big Island on Thursday.
The storm is expected to lash the state with damaging winds, heavy rains and huge waves. It's now on track to remain hurricane-strength or weaken only to a strong tropical storm, said meteorologist Derek Wroe.
Hurricane Julio, meanwhile, swirled closely behind at about 75 mph. Forecasters expect it to slowly strengthen and pass north of the Big Island sometime this weekend. Lixion Avlia, senior hurricane forecaster with National Hurricane Center in Miami, said the storm remained too far away to accurately predict its path.
The two hurricanes have disrupted travel plans, prompted flash flood warnings and led to school closures.
Residents have furiously stocked up on essentials, and Gov. Neil Abercrombie signed an emergency proclamation activating a major disaster fund set aside by the state Legislature.
Hawaii has been directly hit by hurricanes only three times since 1950, though the region has had 147 tropical cyclones over that time. The last time Hawaii was hit with a tropical storm or hurricane was in 1992, when Hurricane Iniki killed six people and destroyed more than 1,400 homes in Kauai, said Meteorologist Eric Lau.
"We've been lucky so far," he said. "So we just need to really take this threat seriously and make sure everybody is prepared."
Residents have seemed to heed that call this week. A grocery store in the coastal Oahu community of Waianae opened 15 minutes early Tuesday because people were already lined up to buy supplies. Bottled water and cans of Spam and Vienna Sausage flew off the shelves, said Charlie Gustafson, general manager of Tamura's Supermarket.
Judy Castillo of Oahu, meanwhile, pushed a cart with two cases of water and other items from a drug store to her car. "Two storms in a row? It's like, Hello?" she said.
The approaching storms prompted public schools on the Big Island, Maui, Molokai and Lanai to close Thursday, state education officials said.
For its part, Hawaiian Airlines will waive reservation change fees and fare differences for passengers who need to alter travel plans because of the storms. The airline said fees will be waived for those who are ticketed to travel Thursday and Friday. They will be allowed to change reservations for flights through Aug. 12.
The clustered storms are rare but not unexpected in years with a developing El Nino, a change in ocean temperature that affects weather around the world.
In the Atlantic Ocean, Tropical Storm Bertha continues to weaken as it moves north, posing no direct threat to the U.S. East Coast. The storm's maximum sustained winds decreased to near 50 mph Tuesday evening with even more weakening expected over the next two days.
On Sunday, the storm buffeted parts of the Bahamas and the Turks & Caicos with rain and gusty winds, after passing over the Dominican Republic. Earlier, it dumped rain on Puerto Rico.
Ahead of this year's hurricane season, weather officials warned that the wide swath of the Pacific Ocean that includes Hawaii could see four to seven tropical cyclones this year.
In preparation, some people in Hawaii are making sure to vote early in the primary elections, which are Saturday. The elections include several marquee races, including primaries for U.S. Senate, governor and a U.S. House seat covering urban Honolulu.
Associated Press Writers Doug Esser in Seattle and Oskar Garcia in Honolulu contributed to this report.