HONOLULU — Hurricane Lane unleashed torrents of rain and landslides that blocked roads on Hawaii’s mostly rural Big Island on Thursday as residents and tourists in the state’s biggest city braced for the dangerous storm to come their way.

Emergency workers rescued five people from a flooded house in Hilo after a nearby gulch overflowed, said Hawaii County Managing Director Wil Okabe. They weren’t injured and were taken to a shelter, he said.

On the state’s most populated island, which is about 200 miles (320 kilometers) north of the Big Island, employees of the Sheraton Waikiki resort filled sandbags to protect the Oahu oceanfront 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.

Hurricane Lane, which was still offshore, already lashed the Big Island with nearly 20 inches (50 centimeters) 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 agency says the storm has weakened to a Category 3 but can still cause major damage.

The hurricane, which was packing maximum sustained winds of 120 mph (193 kph), was expected to move close to or over portions of the main islands later Thursday or Friday, bringing dangerous surf of 20 feet (6 meters), forecasters said.

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 (about 80 centimeters) 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.”

Beimler, who posted videos of trees being blown sideways, said staying put is about the only choice he has. The road to Hilo was cut off due to landslides, he said.

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.

On Oahu, an island of nearly 1 million people, Elisabeth Brinson watching surfers earlier in the day from her balcony on the ninth floor of the Hawaiian Hilton Village in Waikiki. Later Thursday, police on loudspeakers in Waikiki told surfers and swimmers to get out of the water. They said the beach would be closed until further notice.

Hotel staff left a notice that the rooms will still have water and phone service, and a backup generator will power one elevator per building.

Brinson, a native of the United Kingdom now living in Denver, said many shops were closed, and those still open were frantic with people buying food, beer and water to take back to their rooms.

“We knew it was coming, so I tried to just cram as much as I could into the last few days in anticipation so we could cross things off of our list,” said Brinson, who is accustomed to hurricanes after living in Florida.

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.

Members of his association, which include the state’s major hotels, are shifting into high gear with their emergency management plans, he said.

The Marriott Resort Waikiki Beach in Honolulu designated a ballroom on the third floor as a shelter for guests and began removing lounge chairs from around the pool and bar area.

The Queen Kapiolani Hotel brought construction equipment inside from a pool deck that’s under renovation. The hotel will encourage guests to stay in their rooms if the weather worsens and evacuate to hallways if it becomes necessary to avoid windows.

“The only concern is those that venture outside of the properties, that would like to hike on a day like this or who would like to still go into the ocean and see what it’s like to take a swim or surf in these kind of waters,” Hannemann said.

Honolulu shopping malls and office buildings closed early on Thursday and planned to shut their doors Friday.

Shelters were open throughout the islands, with 350 people in them in Oahu. Aid agencies were also working to help Hawaii’s sizable homeless population, many of whom live near beaches and streams that could flood.

Because there’s not enough shelter space statewide, Hawaii Emergency Management Agency Administrator Tom Travis urged people who were not in flood zones to stay home.

The National Weather Service downgraded the Big Island to a tropical storm warning, meaning it expects sustained winds of 39 mph (62 kph) to 73 mph (117 kph) to reach the island instead of stronger hurricane force winds.

But a hurricane warning remains in effect for Oahu and Maui County.

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 (FEMA) 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.