Last Updated Aug 7, 2014 11:15 PM EDT
HONOLULU -- Iselle was supposed to weaken as it slowly trudged west across the Pacific. It didn't - strengthening into a Category 1 hurricane on Thursday and now Hawaii is poised to take its first direct hit in 22 years. Tracking close behind it was Hurricane Julio, which strengthened into a Category 3 storm.
Meanwhile, state officials were assuring the islands were ready for the storms and people should prepare but not panic. At a morning press conference, Gov. Neil Abercrombie stressed that the state is prepared.
"We are fully prepared today as it's possible for us to be, institutionally," he said.
Travelers got their first word of disrupted flights Thursday, when commuter airline Island Air said it was canceling some afternoon flights between the islands and shutting down all operations Friday. Streets normally packed with tourists were empty.
The state Department of Transportation said that no airports were closed and that officials won't decide whether to close them until the storm gets closer.
The outer bands of Hurricane Iselle was expected to arrive on the Big Island on Thursday evening, bringing heavy rains, maximum sustained winds gusting up to 80 mph. It also brings possible waves up to two stories tall and flooding in some areas, CBS News correspondent Bigad Shaban reports from Hilo, Hawaii.
Tom Evans, acting director of the Central Pacific Hurricane Center in Honolulu, told CBS News that the Big Island should start feeling the effects of Iselle around 4 p.m. in Hawaii (10 p.m. ET), but the storm wasn't expected to make landfall until around 8 p.m.
At the White House, President Obama was briefed by his homeland security adviser on preparations for the storms that are threatening his birthplace. Spokesman Josh Earnest said administration officials will remain in close contact with the Federal Emergency Management Agency and other agencies that are preparing to help with response and recovery efforts as the storms near.
Some parts of the islands may see as much as a foot of rainfall by Friday, which could bring power outages, flash floods and landslides, Shaban reported.
That has emergency management officials worried. On Wednesday, they discussed what back-to-back hurricanes could mean for these islands, more than 2,400 miles away from the U.S. mainland.
"It's going to be challenging," Daryl Olivera, the emergency management director for Hawaii County told CBS News. "We're preparing for the full spectrum of impact. That would be everything from power outages, flooding, landslides along our highways."
"There's a limited amount of food on island at any one time - majority of the food is barged in," Barney Sheffield, a disaster coordinator for the American Red Cross, told CBS News.
He said the storms could shut down Hawaii's shipping ports and cut off access to remote communities.
"We're as prepared as you can be, but you never know what's going to come down," Sheffield said.
That uncertainty turned to horror more than 30 years ago, when Hurricane Iwa, a Category 1 storm, left Hawaii with $250 million in damage.
That kind of damage has Ruben Quisisem, a grocery store owner who has lived on the Big Island for 40 years, worried about his livelihood.
"Losing the structure and anything I have inside my store is going to be -- I'm going to lose my business, of course," he said.
Weather officials changed their outlook on the system Wednesday after seeing it get a little stronger, giving it enough oomph to stay a hurricane as it reaches landfall.
"What ended up happening is the storm has resurged just enough to keep its hurricane strength," said Mike Cantin, a National Weather Service meteorologist.
Cantin said that means stronger winds of 60 to 70 mph, though rainfall estimates of 5 inches to 8 inches in a short time frame remained unchanged.
"Not a major hurricane, but definitely enough to blow things around," he said.
Cantin said the Big Island's size and terrain would help break up the hurricane, weakening it into a tropical storm as it passes Maui and Oahu late Thursday and early Friday.
Hurricane Julio, meanwhile, swirled closely behind with maximum winds whipping at 115 mph. The National Hurricane Center said it expected the storm to strengthen even more Thursday before gradually weakening by Thursday night. That weakening is expected to continue into the weekend.
Hawaii has been directly hit by hurricanes only three times since 1950, though the region has had 147 tropical cyclones over that time. The last time Hawaii was hit with a tropical storm or hurricane was in 1992, when Hurricane Iniki killed six people and destroyed more than 1,400 homes in Kauai, said meteorologist Eric Lau.
The two hurricanes have disrupted tourism, prompted flash flood warnings and led to school closures. Abercrombie, meanwhile, signed an emergency proclamation allowing officials to tap into a disaster fund set aside by the state Legislature.
On top of it all, as the two hurricanes churned toward the islands, a magnitude-4.5 earthquake hit Hawaii's Big Island at about 6:30 a.m. local time, the U.S. Geological Survey reported.
The temblor struck on the island's north tip, about 7 miles from Waimea. There were no immediate reports of damage.
Kelsey Walker said the quake felt like a "little jolt" but didn't knock things off shelves at the Waimea grocery store where he works. He was trying to keep a sense of humor about it.
"We have a hurricane. Now we have this on top of it. What else?" said Walker, second assistant manager at Foodland Waimea.