Hurricane Madeline showed power as it headed toward Hawaii Tuesday, reaching a dangerous Category Four strength before slackening somewhat, 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 1500 GMT, the center rated Madeline as a Category Three storm with maximum sustained winds around 120 miles (195 kilometers) per hour.

That was slightly weaker than at 1200 GMT when it reported that Madeline's winds were peaking at 130 miles (215 kilometers) per hour, making it a dangerous Category Four storm.

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.

At 1500 GMT, the massive storm was about 445 miles (715 kilometers) east of Hilo, Hawaii, traveling at 10 miles (17 kilometers) per hour toward the west.

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

"Some weakening is forecast through early Thursday."

The US weather agency said swells generated by Madeline are expected to reach the Hawaiian Islands over the next couple of days, including some strong enough to be damaging to the coastline.

Madeline is expected to dump five to 10 inches (12.7 to 25.4 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.