Powerful storm set to wreak havoc on Hawaii

A strong storm packing high winds and extremely heavy rain flooded roads and knocked out power across Hawaii, with United States officials warning on Monday of potentially worse conditions ahead.

The National Weather Service said the storm brings the threat of "catastrophic flooding" in the coming days as a low pressure system slowly moves from east to west and lingered on the edge of the archipelago.

"Now is the time to make sure you have an emergency plan in place and supplies ready should you need to move away from rising water," said Governor David Ige, who issued a state of emergency for all of the state's islands on Monday night.

On Oahu, where four shelters had been opened, most of the beaches in Waikiki were empty on Monday as only a few people walked with umbrellas during passing heavy showers. Roadways were flooding in the area and cars crept through downtown as water gushed out of manhole covers.

Honolulu Fire Department workers rescued five boys, ages 9-10, from a raging stream, a fire department statement said.

On Maui, power outages and flooding have been reported, with more than 30 centimeters of rain falling in some areas.

Big Island Mayor Mitch Roth declared a state of emergency on Sunday for potentially heavy rainfall and strong winds.

All islands still face the threat of flash flooding, lightning strikes, landslides and strong winds over the next two days, according to the National Weather Service.

Oahu and Kauai could see the brunt of the storm on Monday and yesterday. But for Maui and the Big Island, which have already been soaked, "it's not going to take a lot of additional rain to really lead to big problems," said National Oceanic and Atmospheric Administration meteorologist Robert Ballard.