Hurricane Lane strengthened to a powerful Category 5 storm late Tuesday as it made its way to a dangerously close encounter with the Hawaiian Islands in the coming days.

Although it is not certain whether the storm, packing peak winds of 160 mph, will directly strike the islands or just graze them, significant effects from rain, wind and waves are becoming increasingly likely.

The National Weather Service issued a hurricane warning Tuesday evening for the Big Island, as Hawaii island is known. Hurricane watches are in effect for Maui, Oahu — home to the state capital — and other small islands. Tropical-storm-force winds and heavy rain could affect those areas as soon as Wednesday or Thursday.

Because of the shape of Lane’s projected path, which may parallel or track over the entire island chain, all of the islands may face hazards from the storm.

The storm may bring “damaging winds and life-threatening flash flooding from heavy rainfall,” the weather service’s Central Pacific Hurricane Center warned. “As Lane is expected to be slow-moving as it nears the islands, it will produce large and damaging surf, mainly along exposed south and west facing shores,” it added.

The National Weather Service warned that considerable damage to roofs are possible, and that some locations may be uninhabitable for weeks.

Residents raced to grocery stores Tuesday, stocking up on bottled water, paper towels and toilet paper.

While hurricanes and tropical storms frequently roam close to the islands, direct hits are rare. The last hurricane to make landfall in Hawaii was Iniki in 1992, which struck Kauai.

“This isn’t Florida. The landscape and infrastructure are different. Take this one seriously,” tweeted Michael Lowry, a strategic planner at the Federal Emergency Management Agency and a tropical weather expert.

Gov. David Ige said he will allow non-essential state employees on the Big Island and Maui to go on administrative leave from Wednesday to Friday.

Lane could become the first hurricane to directly make landfall in Honolulu since Hawaii became a state, Axios reported. “If the storm were to make a significant impact on the island of Oahu, in particular, it could cause flooding at Honolulu International Airport, the oil refinery at Barbers Point, and several large military installations, including Joint Base Pearl Harbor-Hickam,” it noted.

While the Big Island, at most immediate risk from Lane, has been hit by tropical depressions and storms, it also has never been struck directly by a hurricane-strength storm in modern records.

The Hurricane Center urged residents of Hawaii to prepare for the storm. In Kona, on the Big Island, it cautioned that at least 10 to 15 inches of rain could fall, with isolated amounts greater than 20 inches over the Hawaiian islands.

Late Tuesday, Lane was positioned about 350 miles south-southeast of Kona, tracking west-northwest at 9 mph. Over the next day, the storm is predicted to turn more to the north, but how sharply is the critical question. The sharper the turn to the north, the more likely one or more islands will endure a direct hit. If the storm pursues more of a westerly course, it may just brush the islands.

“It is much too early to confidently determine which, if any, of  the main Hawaiian Islands will be directly impacted by Lane,” the Hurricane Center said. “Even if the center of Lane were to remain offshore, it is important to  remember that impacts from a hurricane can extend well away from the center.”

While the storm has gained strength over the past day, reaching Category 5 strength late Tuesday, the Hurricane Center predicts it to begin slowly weakening over the next 48 hours because of increasing wind shear, which would disrupt thunderstorm development.

However, the storm has attained an annular structure, meaning its large eye is surrounded by a single, uniform ring of thunderstorms. Just 4 percent of hurricanes and typhoons are annular, and they are known for their staying power, weakening more slowly under unfavorable conditions, compared with conventional storms.

In other words, Lane is likely to maintain hurricane strength when it makes a close approach or direct strike Thursday on the Big Island. It may take until the weekend for Lane to succumb to wind shear and weaken to a tropical storm.