Kona, Hawaii • A powerful hurricane that already has dumped more than two feet of rain on parts of the Big Island is expected to keep soaking the state through the weekend, exacerbating dramatic flood conditions as residents hunker down and wait for the storm to pass.

Officials downgraded Hurricane Lane to Category 2 on Friday morning but say threats of landslides, storm surge and flooding remain a major concern because the storm has slowed in speed. The crawl along the island chain's edge gives the hurricane more time to unleash more rain over Hawaii before it weakens and makes an expected break to the west sometime Saturday.

"This is going to be a marathon-based event," FEMA Administrator William "Brock" Long said in a news conference Friday morning. "The bottom line is we're going to see torrential rains occur for the next 48 to 72 hours and we hope that all the citizens within Hawaii are heeding the warnings that local and state officials are putting out."

The storm has caused power outages, felled trees and shut down roads across the state.

Drone video of downtown Hilo on the east side of Hawaii's largest island shows large swaths of the area covered in brown, murky floodwaters. Some parts of the Big Island have seen more than 31 inches of rain, more than double the 12 inches reported Thursday morning.

Rainfall totals could surpass 40 inches in some areas, according to The Washington Post's Capital Weather Gang. As of Friday afternoon, Hurricane Lane was tracking about 180 miles southwest of Honolulu, churning north at 5 mph.

Storm preparation efforts have been complicated on the island of Maui, where emergency crews have been responding to a huge brush fire in the Lahaina area. The fire started at about 1 a.m. and spread to hundreds of acres. More than 100 homes have been evacuated. Officials said it's unclear if the cause of the fire is related to the storm, but the high winds have been stoking it, and the response has been sapping resources that were going toward Hurricane Lane.

"This is one of the worst fires that we've ever had," Maui County Mayor Alan Arakawa told a local news station early Friday morning.

Arakawa said the National Guard has come in to assist and that some people sheltered at a local school were taken to a civic center to make room for those pushed out because of the fires.

More than 1,500 people have been waiting out the hurricane in shelters, with about 1,000 of them in Oahu. Sirens blared throughout Oahu at 4 p.m. Thursday warning residents to take shelter.

"I do expect an increase in population as the storm continues to approach," said Brad Kieserman, vice president for disaster operations for the American Red Cross, adding that he expected more shelters to open Friday.

Long, the FEMA administrator, asked people to be patient in the aftermath of the storm, warning that Hurricane Lane is expected to cause continued power outages and infrastructure damage.

"They're called disasters because stuff is broken after the fact," Long said. "Citizens need to realize we're looking at major hurricane impacts. Things are going to break. We need to set the expectation that the power can go off for quite some time and the infrastructure is going to be heavily impacted."

The storm left many tourists stranded or scrambling to make new plans, with several airlines canceling flights out of Kahului International Airport.

Francis Dybczak, 48, and his wife Shannon, 36, had been married for less than a week when Hurricane Lane started heading toward the Hawaiian Islands. The Toronto couple had been looking forward to their honeymoon too much to call it off. But when they arrived on Monday and headed to their condominium in the resort area of Ka'anapali Beach, it was already becoming clear that Lane could have serious implications.

Dybczak, who works at the Toronto airport, worried that the hurricane could delay their Saturday flight back to Canada.

"I wasn't necessarily worried about the wind, I was more concerned about what could come after, like the flooding," he said. "And I have to be at work Monday."

Reluctantly, the couple decided to change their Hawaiian Airlines flight to Thursday evening - a feat that required numerous calls to the airline and multiple trips to the airport. "We're going to have a stay-moon in Toronto, I guess," Dybczak said.

As many people were rushing to leave Maui late Thursday afternoon, James Broad, a lawyer who lives in Hong Kong, had just arrived. Broad, 29, of the U.K., scheduled the trip to celebrate his impending 30th birthday, and he spent 20 hours in transit to get to the tiny island.

"The weather is probably better in the U.K. this week," he said, "but there's nothing I can do. … It's my birthday and I couldn't change the plans, and anyway, my family is coming from England to meet me here."

In the mostly shuttered and sandbagged tourist town of Paia, the Flatbread Company stood out as one of the few places where tourists and locals could grab lunch Thursday.

Nick Rodriguez, 42, a manager, stood behind the counter amid tables full of diners, putting in orders, cutting pizzas and serving them. He's lived in Texas and Florida and has been through at least 10 hurricanes.

"We decided to stay open because there have been times in the past when we've closed too early because of a storm that never hit hard," he said. Flatbread Company was doing even better business than usual. The bar and most of the booths and tables were full, with several families waiting outside for a table. The air was filled with the smell of sizzling cheese as a light rain fell outside.

Rodriguez said the restaurant would close for dinner, allowing employees ample time to get home in case roads became impassible.

"The main concern is flooding," Rodriguez said. "The infrastructure here is not that great, and it's common for trees to go down, to cut off power or roads, which makes certain parts of the island inaccessible. And we want people who work here to be able to get home to their families."

The Washington Post’s Jason Samenow contributed to this report.