It declares counties of "Hawai'i, Maui, Kalawao, Kaua'i and the City and County of Honolulu disaster areas for the goal of implementing emergency management functions", his office said.
Even if the centre of Lane doesn't make landfall, the islands could be walloped with rain and wind.
The service warned that the hurricane is still forecast to be extremely unsafe as it gets closer to the islands.
Hurricane Lane spun in a dangerously unpredictable path Friday as it lumbered toward Hawaii, dumping rain on the mostly rural Big Island and forcing more than 1,000 people to flee to emergency shelters.
Lane may also generate surf heights reaching as much as 7.5 metres, with "the potential for significant damage to coastal properties and infrastructure, including roadways".
"It was quite an experience because we weren't planning to have a hurricane during our vacation time", Demerais said.
"We are fully stocked", she said.
Lane's wind speeds increased to almost 250 kilometers per hour (155 mph) as it moved west. In Kona, on the Big Island, it cautioned that at least 4 to 8 inches of rain could fall and that winds could exceed tropical-storm force (39 mph).
As Hurricane Lane bears down on Hawaii, three dozen people from California were preparing Wednesday to leave for the islands to help in the relief effort.
The weather service says that in a Category 5 hurricane, a high percentage of framed homes will be destroyed.
So far, American Airlines and Hawaiian Airlines are still running flights into Hawaii, but are issuing travel advisories to passengers. Both are waiving reservation change fees as the hurricane approaches. Lane is making a northerly turn toward the Hawaiian Islands, increasing wind and weather impacts to the islands through the rest of the week - all islands are now under a hurricane watch or warning.
"Isolated rainfall amounts of 20" + are possible. Do expect possible heavy rain leading to flash flooding.
The downpours could lead to landslides and flooding. This major category 4 hurricane is expected to make a turn towards the Hawaiian Islands this week.
More hurricane watches were expected to be issued for other Hawaiian islands, said the Honolulu-based hurricane center.
The National Weather Service said tropical-storm-force winds could begin as early as Wednesday afternoon on the Big Island.
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