Hurricane Lane weakened to a tropical storm on Friday as it headed toward the Hawaiian islands.

But it still brought torrential rains that immersed a city in waist-deep water and forced people to flee flooding homes, while others jumped off seawalls with boogie boards into the turbulent ocean.

As many dealt with flooding and even brush fires, swimmers and surfers ignored warnings from authorities and plunged into powerful waves at the Oahu’s famed Waikiki Beach, which was closed.

Emergency officials said repeatedly over loudspeakers: “Please get out of the water! It’s very dangerous!”

Swimmers get tossed around at Makapu’u Beach in Waimanalo, Hawaii
Swimmers get tossed around at Makapu’u Beach in Waimanalo, Hawaii (AP Photo/Marco Garcia)

Honolulu’s mayor pleaded with tourists that they were putting themselves in danger as the storm moved closer.

The US National Weather Service downgraded the storm to a tropical storm with winds of up to 70 mph as it headed north toward the islands.

It was expected to veer west, skirting the islands, but still threatened to bring heavy rains and strong, gusty winds across the state, meteorologist Gavin Shigesato said.

A hurricane watch for Hawaii’s westernmost inhabited islands, Kauai and Niihau, was downgraded to a tropical storm watch.

But the hurricane centre warned that Lane could trigger flash flooding and inflict wind damage.

The outer bands of the storm dumped as much as three feet of rain on the mostly rural Big Island in 48 hours. The main town of Hilo, population 43,000, was flooded on Friday with waist-high water as landslides shut down roads.

People look over the Wainaku Street bridge as Wailuku River rages below them in Hilo, Hawaii
People look over the Wainaku Street bridge as Wailuku River rages below them in Hilo, Hawaii (Hollyn Johnson/Hawaii Tribune-Herald via AP)

Elsewhere on the Big Island, the National Guard and firefighters rescued six people and a dog from a flooded home, while five California tourists were rescued from another home.

A different type of evacuation took place on Oahu.

Officials with Hawaii’s Department of Land and Natural Resources transferred about 2,000 rare Hawaiian snails from a mountain marsh to offices in Honolulu.

Some of the snails are literally the last of their kind.

In Waikiki, the man-made Ala Wai Canal is likely to flood if predicted rains arrive, said Ray Alexander of the US Army Corps of Engineers.

“The canal has flooded in the past, and I believe it’s safe to say based on the forecast of rainfall it’s likely to flood again, the impacts of which we aren’t prepared to say at this time,” he said.

People walk by sandbags stacked up to protect a store near Waikiki Beach
People walk by sandbags stacked up to protect a store near Waikiki Beach (AP Photo/John Locher)

Employees have filled sandbags to protect oceanfront hotels from surging surf. Stores along Waikiki’s glitzy Kalakaua Avenue stacked sandbags along the bottom of their glass windows to prepare for flash flooding, while residents lined up at stores to stockpile supplies.

Almost 16,000 homes and businesses on the islands lost power as the outer edges of the storm battered the islands, but service was restored to some.

The central Pacific gets fewer hurricanes than other regions, with about only four or five named storms a year. The last major storm to hit Hawaii was Iniki in 1992.