How soon it turns and how sharp it turns will determine how close the center gets to the islands and how much damage it will cause.
FEMA administrator Brock Long said the supplies arrived in Hawaii after a volcano began oozing lava into neighbourhoods in May and in preparation for a recent hurricane that bypassed the islands.
People have been rushing to stores for supplies.More news: Zach Smith's attorney blames Courtney's 'vengeance' for causing issues
"(I'm) filling up my bathtub with some water, hoping to board up my main windows in time", a shopper on the Big Island, Shana Bartolome, told CNN affiliate KHON on Tuesday.
Ige said officials were expecting some roads to flood and residents should refrain from driving.
"Rain has been nonstop for the last half hour or so and winds are just starting to pick up", Beimler said as he posted videos of trees being blown sideways.
Unlike Florida or Texas, where residents can get in their cars and drive hundreds of miles to safety, people in Hawaii are confined to the islands and can't outrun the powerful winds and driving rain. Hurricane-force winds will extend up to 40 miles out from the storm's center; tropical-storm-force winds will extend up to 140 miles.
The storm is moving closer to the Hawaiian islands with sustained winds of 145 miles per hour and forecasters say it's "on course to pass very close" to the islands or make landfall from Thursday through Friday.More news: Eden Hazard coy over long-term Chelsea future
The Central Pacific Hurricane Centre announced on Wednesday evening that a hurricane warning is in effect for Oahu island, as well as Big Island, Maui, Lanai, Molokai and Kahoolawe.
U.S. Navy ships and submarines based in Hawaii were instructed to leave port, a common practice as a hurricane approaches to avoid damage.
He says the more stationary hurricane increases the threat of flash floods and landslides because of prolonged, increased rainfall.
Widespread rainfalls of 10 to 15 inches are possible, with more than 20 inches possible in some spots. Originally the storm was a category 5 but recently weakened to a category 4.More news: Madonna defends herself after Aretha Franklin tribute backlash
A small group of volunteers from Arizona traveled to Hawaii with the American Red Cross on Wednesday to help residents prepare for and recover from an incoming hurricane.