Hurricane Lane is slowly making its way north-northwest off Hawaii while lashing Hawaii’s Big Island as residents and tourists braced for the dangerous storm.

Lane was not projected to make a direct hit on the islands, but officials warned that even a lesser blow could do significant harm. Some areas could see up to 30 inches of rain.

"Rain has been nonstop for the last half hour or so, and winds are just starting to pick up," said Pablo Akira Beimler, who lives on the coast in Honokaa on the Big Island. "Our usually quiet stream is raging right now."

The National Weather Service announced late Thursday that a Tropical Storm Warning has replaced a Hurricane Warning for the Big Island, but called flooding a major concern. Emergency crews in Hilo already rescued five people from a flooded house after a nearby gulch overflowed.

The biggest threat early Friday was issued for Maui and Oahu, which is expected to be pummeled by heavy rains and wind.

Employees of the Sheraton Waikiki resort, on Oahu, filled sandbags to protect the hotel from surging surf. Stores along Waikiki's glitzy Kalakaua Avenue stacked sandbags along the bottom of their glass windows to prepare for heavy rain and flash flooding.

Hawaii's biggest hotels are confident they can keep their guests safe as long as they stay inside, said Mufi Hannemann, CEO of Hawaii Tourism and Lodging Association.

United Airlines cancelled its Friday flights to and from Maui. The airline added two additional flights from Honolulu to San Francisco on Thursday to help transport people off the islands.

Hawaiian Airlines cancelled all Friday flights by its commuter carrier, Ohana by Hawaiian.

Hurricane Lane, which was still offshore, already lashed the Big Island with nearly 20 inches of rain in nearly 24 hours and was moving closer, putting it and Maui "in the thick" of the storm, National Weather Service meteorologist Melissa Dye said.

The central Pacific gets fewer hurricanes than other regions, with about only four or five named storms a year. Hawaii rarely gets hit. The last major storm to hit was Iniki in 1992. Others have come close in recent years.

Because people in Hawaii are confined to the islands, they have to make sure they have enough supplies to outlast power outages and other potential emergencies.

The Federal Emergency Management Agency moved several barges packed with food, water, generators and other supplies into the region ahead of Hurricane Hector, which skirted past the islands more than a week ago, FEMA Administrator Brock Long said.

The Associated Press contributed to this report