Hurricane Madeline showed power as it churned toward Hawaii on Tuesday, peaking at a dangerous Category Four strength before slackening, US weather officials said.

The storm, which is expected to pass near Hawaii's Big Island sometime Wednesday, has the potential to unleash dangerous flash floods and mudslides, the Central Pacific Hurricane Center said.

At 0900 GMT Wednesday, Madeline was a Category One storm with maximum sustained winds around 90 miles (145 kilometers) per hour with higher gusts.

Winds had reached 130 miles per hour earlier in the day, making the hurricane a Category Four storm at the time.

A hurricane warning is in effect for Hawaii County and tropical storm watch for Maui Country, which includes the islands of Maui, Molokai, Lanai and Kahoolawe.

Madeline threatens to disrupt a planned visit by President Barack Obama and other dignitaries to Hawaii for the World Conservation Congress, a major meeting of thousands of delegates, including heads of state, scientists and policy makers.

The massive storm was located some 235 miles east of Hilo, Hawaii, traveling west around 12 miles per hour.

"On the forecast track, the center of Madeline will pass dangerously close to Hawaii County Wednesday and Wednesday night," the center said in its advisory, referring to the Big Island.

Madeline was expected to gradually weaken over the next 48 hours.

Hurricane-force winds extended 25 miles from the center of the storm, while tropical storm-force winds extended out 125 miles.

The US weather agency said swells generated by Madeline were expected to affect eastern shorelines beginning later Tuesday, with some strong enough to damage the coastline in the coming days.

Madeline is expected to dump five to 10 inches (13 to 25 centimeters) of rain on Hawaii, with some areas receiving up to 15 inches.

The World Conservation Congress is set to take place in Hawaii from Thursday to next Saturday.

Obama is scheduled to address the gathering on its opening day.