Hurricane Lane is threatening a direct hit on Hawaii and could become the most powerful storm to reach the archipelago in a quarter of a century.
Schools, governments and businesses have closed while residents stocked up on food, water and other supplies and boarded up homes.
The hurricane, classified as a powerful Category 4 storm, was packing sustained winds of up to 145mph (230 km/h) and could dump as much as 20in of rain over parts of the US Pacific island state, triggering flash flooding and landslides, the National Weather Service (NWS) warned.
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21:29
Two campers are trapped in a valley on the Big Island's north coast according to state emergency personnel.
The pair called in on Wednesday to report the heavy rains from Hurricane Lane's approach made it impossible for them to get out of the Waipio Valley and authorities have been unable to reach them since due to spotty mobile reception.
Emergency crews cannot access their location safely because of landslides and continued rain, Hawaii County Managing Director Wil Okabe told the Associated Press.
20:59
Here's an animation done by the National Weather Service in Hawaii. They tweeted "rain, rain, and more rain!"
The lower wind speed of the hurricane may sound like a positive note but it does prolong the rain, which leads to inland flooding, landslides, road closure, and possibly infrastructure damage.
20:40
Donald Trump has responded to the preparations for Hurricane Lane. The president tweeted "teams are closely coordinating with the state and local authorities. You are in our thoughts!"
He included a link to a story from Fox News, his favoured news outlet, with the tweet.
After criticism of the president and FEMA's response to another island hurricane disaster in Puerto Rico, the administration may be more prepared for this one, according to many Washington watchers.
You can read more about what happened in Puerto Rico during and after Hurricane Maria in 2017, here:
19:47
FEMA administrator Brock Long said there "is a lot of uncertainty" about the hurricane's forecasted path and intensity.
“What is for sure: Hawaii is going to be impacted. The question is: how bad?," he said at a news conference ahead of the storm's landfall.
Mr Long said the agency is looking at forecasts which predict 30 inches (76cm) in some parts of the island state.
Flooding inland, landslides, and infrastructure damage are all concerns the agency is preparing to handle for at least the next four to five days.
He also mentioned FEMA is in touch with major grocers in the affected areas in an attempt to coordinate.
Honolulu Mayor Kirk Caldwell has also been holding news conference to address concerns.
19:28
The last time a major hurricane hit Hawaii was 11 September 1992. Hurricane Inki was a Category 4 storm just like Lane.
When Inki made landfall it passed north of Kauai it caused $3bn (£2.3bn) in damages.
The Red Cross estimated it had destroyed or damaged nearly 15,000 homes and remains the costliest storm to hit the islands.
Six people were killed from injuries related to the hurricane and more than 100 were injured.
19:04
Hawaii has been no stranger to dire natural disasters this year. Mount Kilauea, located on the Big Island, has been spewing lava all summer along the southeastern coastline.
Fortunately for residents new lava flow stopped on 9 August according to the Hawaiian Volcano Observatory. Without much lava reaching the ocean the hurricane may not have too much of an impact on the volcano area, Denison University Geophysicist Erik Klemetti told CNN.
Read more about our coverage of the volcano and the damage it caused here:
18:22
A search and rescue team of 36 members based in Menlo Park, California, has been sent to Hawaii ahead of Hurricane Lane's landfall.
California Urban Search and Rescue Task Force 3 is one of 28 such teams across the country, eight of which are based in California.
Menlo Park Fire Protection District Chief Harold Schapelhouman told the local CBS News affiliate: "The task forces are the Swiss Army knives of technical rescue operations and this configuration is specific to a smaller, more focused, water rescue capable unit that can operate in a dynamic field environment for 10 to 14 days".
Along with the crew, approximately 40,000lb (18,000kg) of technical search and rescue equipment is also headed to the islands.
17:39
Torrential downpours are soaking Hawaii's Big Island as the storm approaches and meteorologists have recorded 12 inches (30cm) of rain in the town of Hilo as of 4am local time.
Maui County is also reporting bands of rain for 350 miles (563km) along the centre of the hurricane.
16:34
Some residents have expressed worry to about what will happen if the hurricane is more devastating than expected and if the federal government's response will be the same as it was in Puerto Rico in 2017.
Unlike many residents of Florida during Hurricane Irma and Texas at the time of Hurricane Harvey who had some option to travel outside of the path of the storms,
many Puerto Ricans had nowhere else to go for safety from Hurricane Maria because they were on an island.
The US government and Federal Emergency Management Agency's (FEMA) response to disaster relief were widely criticised for being near-sighted and ill-prepared. It took nearly 9 months and $4bn to restore electricity to the island.
FEMA administrator Brock Long did confirm the agency has several barges with food, water, and supplies it moved into the region ahead of Hurricane Hector, which skirted past the islands more than a week ago.
16:15
The US National Weather Service said Hurricane Lane is "making northward turn" as had been forecast. Wave heights have reached nearly 23 feet (7m)
14:38
Of concern on the island of Oahu, which was put on a hurricane warning late Wednesday, is Hawaii's fairly large homeless population.
Many of them live near beaches and streams that could flood and may not have been alerted in time to get to open shelters.
Hawaii Emergency Management Agency Administrator Tom Travis said there's not enough shelter space statewide and advised those who are not in flood zones to stay home.
Officials said shelters are supposed to be a "last resort" since many are not designed to handle winds of more than 40 mph (64 kph).
14:22
Donald Trump has declared a state of emergency for Hawaii, just hours before the Category 5 storm is expected to make landfall.
Federal assistance will now be provided to help state and local governments as they brace themselves, particularly on the islands of Maui, Lanai, Molokai and Kahoolawe.
"We encourage all those in the path of the storm to listen to the instruction of state and local authorities as it relates to evacuation orders and shelter locations," White House press secretary Sarah Huckabee Sanders said during a briefing.
Honolulu Mayor Kirk Caldwell told Hawaii News Now: "Some people might say, 'Another hurricane, it didn't hit us last time, we don’t need to worry,'" he continued. "No, we got to plan for the worst and hope for the best."
14:00
The AFP news agency has published a useful infographic explaining the different parts and structure of a hurricane.
13:43
The Red Cross has said it is preparing to respond to Hurricane Lane by getting workers and supplies ready.
13:21
"We expect it to gradually weaken as it gets closer to the islands," Mr Chevalier said.
Chevy Chevalier, a meteorologist, told the Associated Press that Hurricane Lane may drop to a Category 3 storm by Thursday afternoon but said it would still be a major hurricane.
"We expect it to gradually weaken as it gets closer to the islands," Mr Chevalier said.
"That being said, on our current forecast, as of the afternoon on Thursday, we still have it as a major hurricane."
12:59
"We're getting some bags of rice and of course, some Spam," she said of the canned lunch meat that's popular in Hawaii.
She was organising important documents into a folder — birth and marriage certificates, Social Security cards, insurance paperwork — and making sure her three children, all under 4, have flotation devices such as swimming vests — "just in case."
As emergency shelters opened, rain began to pour and cellphone alerts went out, the approaching hurricane started to feel real for Hawaii residents.
"Everyone is starting to buckle down at this point," Christyl Nagao of Kauai island told the Associated Press.
"Our families are here. We have businesses and this and that. You just have to man your fort and hold on tight."
Melanie Davis, who lives in a suburb outside Honolulu, said she was gathering canned food and baby formula.
"We're getting some bags of rice and of course, some Spam," she said of the canned lunch meat that's popular in Hawaii.
She was organising important documents into a folder — birth and marriage certificates, Social Security cards, insurance paperwork — and making sure her three children, all under 4, have flotation devices such as swimming vests — "just in case."
12:43
City residents used carts to push cases of bottled water and coolers full of ice, after warnings of possible power outages and evacuations.
Cars waited in long lines at gasoline stations in Honolulu and people could be seen pulling small boats from the water ahead of Lane's expected storm surge.
"I went to Safeway last night for regular groceries, everyone was in a panic," said Thao Nguyen, 35, an employee at a Honolulu branch of Hawaiian shirt retailer Roberta Oaks.
"People were buying cases of tiny water bottles.
The shelves of a downtown Honolulu Walmart were stripped of items ranging from canned tuna to dog food, Reuters reports.
Shoppers jostled with one another to get the last boxes of ramen noodles.
"There's nothing in there," said one shopper leaving the store.
"There's nothing in there," said one shopper leaving the store.
City residents used carts to push cases of bottled water and coolers full of ice, after warnings of possible power outages and evacuations.
Cars waited in long lines at gasoline stations in Honolulu and people could be seen pulling small boats from the water ahead of Lane's expected storm surge.
"I went to Safeway last night for regular groceries, everyone was in a panic," said Thao Nguyen, 35, an employee at a Honolulu branch of Hawaiian shirt retailer Roberta Oaks.
"People were buying cases of tiny water bottles.
Additional reporting by agencies
