Hurricane Julio has gained strength to transform into a Category 3 storm with a maximum sustained speed of 115 mph, making it the fourth major hurricane of the eastern Pacific season. Meanwhile, Hawaii prepared for Hurricane Iselle, its first hurricane in 22 years, which is expected to make landfall overnight.

Julio, which is expected to pass north of the islands on Sunday morning, is reportedly more than 1,000 miles behind Iselle. Iselle, a Category 1 hurricane, was slated to make landfall on Hawaii’s Big Island, sending high winds and rain to the rest of the state on Friday. National Weather Service meteorologist Eric Lau reportedly said that they have been evaluating all storm data before making changes to the storms' classification.

"But we're not really too concerned about the track or the intensity of the system," Lau told Associated Press, or AP. "We're primarily urging residents to still take proper precautions to prepare themselves to keep everyone safe."

Two communities on the Big Island -- Waimea, a town of about 9,200 people and Puna, one of the nine districts located in the eastern part of the island -- were without power Thursday evening, Hawaii County Civil Defense officials said, according to AP, while an evacuation shelter in Pahoa, which had at least 140 people, had also lost power.

Many airlines, including Delta, United, US Airways, American Airlines, Air China and WestJet, canceled their flights on Thursday, Hawaii Tourism Authority said, according to AP.

The Hawaii National Guard also reportedly sent many of its aircraft to bases on the West Coast to avoid damages from the storm.

According to Reuters, Hawaii’s two refineries -- run by Par Petroleum Corp (OTCMKTS:DPTRQ) and Chevron Corporation (NYSE:CVX) -- were also reportedly securing their plants on the island of Oahu on Thursday.

Early Thursday, a 4.5 magnitude earthquake rattled Hawaii even as residents were preparing for the arrival of the two hurricanes. There were no immediate reports of damages and no tsunami warning was issued.

"What we're asking the people to do now is pay attention, stay focused and listen to the directions," Hawaii Gov. Neil Abercrombie said, according to AP.