Two hurricanes are now taking aim at Hawaii.
Residents are lining up at gas stations and flooding grocery stores.
The first, Hurricane Iselle, packed 90 mph wind on Wednesday as it chugged west toward the islands, and forecasters said that while it was expected to weaken, it could still be hurricane strength at landfall on Thursday.
The trailing system, Hurricane Julio, was upgraded from a tropical storm. It had winds of 75 mph, just strong enough to make the cut. While it could jog to the north, the projected path still had the storm hitting Hawaii on Sunday night.
Gov. Neil Abercrombie encouraged islanders to make an emergency plan, and people stocked up on bottled water and other supplies.
"Days like today, in a situation like this, we just throw open the doors and hold on for the ride," Scott Ankrom, assistant general manager of a Costco store in Hawaii, told The Associated Press.
Hawaii is also holding primary elections on Saturday for races including a Senate seat, the governorship and the House seat that represents Honolulu. Some islanders are voting early ahead of the weather.
Iselle has weakened slightly already. It was a Category 4 hurricane as recently as Monday, with top wind of 140 mph, but was downgraded to a Category 1 by early Wednesday.
Whether it strikes as a tropical storm or a hurricane, "We’ll have power outages likely from all the wind, and maybe some flooding as well from all the heavy rain," said Ari Sarsalari, another meteorologist for The Weather Channel.
The two tropical systems are being steered west toward the islands by the underside of a high-pressure system in the Pacific Ocean. Tropical storm watches were posted for the Big Island of Hawaii and for Maui, just to the west.
Hawaii hasn't been hit by a tropical storm or hurricane at all since 1992. And the one-two punch would be unprecedented in the era of satellite hurricane tracking, said Kevin Roth, a meteorologist for The Weather Channel.
The closest similar occurrence was in the summer of 1982, when a weakened Tropical Depression Daniel struck Hawaii and was followed 10 days later by Tropical Storm Gilma.