Hurricane Lala weakened to a tropical storm on Sunday after skirting Hawaii without making landfall, but continued to punish the Big Island with hurricane-force gusts, heavy rainfall, and dangerous flooding.

Total rainfall of nearly three feet, or one meter, was expected on the higher windward slopes, turning rivers into raging torrents and threatening mudslides. Powerful waves pounded the Big Island's coast as Lala slowly passed by, with howling winds whipping palm trees and waterways swelling with fast-moving runoff from relentless rain that blew nearly sideways.

Tropical storm conditions spread westward on Sunday from Maui to Oahu and then Kauai. The National Hurricane Center warned that wind speeds atop mountains and on windward and leeward slopes are often up to 30% stronger than the near-surface winds used to categorize storms.

More than 130,000 households were without power Sunday morning across Hawaii's three largest islands, according to the utility tracker poweroutage.us. At least three hospitals were operating on generator power, Gov. Josh Green said.

At least one person died in a car accident in the South Point area of the Big Island. The governor said Saturday evening that 19 roofs were lost in the "enormous storm" and that more than 30 road sites had already been attended to by repair crews.

"There have been a lot of roads impacted, our crews have already been out to more than 30 sites," Green said.

A search-and-rescue mission involving Civil Defense, the National Guard, and the Coast Guard was launched after flash floods apparently swept several occupied homes off their foundations in the coastal communities of Na'alehu and Wai'ohinu, near the island's southern tip. Hawaii County Mayor Kimo Alameda announced the operation early Sunday.

"What makes this very challenging is that there's rushing water, there's debris, and there's boulders on the road and it's dark," Alameda said.

Tropical storm warnings were in effect for the islands of Maui, Molokai, Lanai, Kahoolawe, Oahu, Kauai, and Niihau as the storm moved west, raising the possibility of destructive flooding and wildfires driven by strong winds.

As of 2 a.m. Sunday local time, Lala was centered approximately 105 miles, or 170 kilometers, west-northwest of Kailua-Kona and about 100 miles, or 160 kilometers, south of Honolulu. Tropical-storm-force winds extended as far as 175 miles, or 280 kilometers, from its center. The storm was sustaining top winds of 70 mph, or 110 kph, and moving northwest at about 15 mph, or 24 kph.

Forecasters expect Lala to regain hurricane strength midweek once it moves well west of the island chain.

By the time the storm passes entirely, some higher-altitude locations on the Big Island, dominated by the towering Mauna Kea volcano, are forecast to receive as much as 35 inches, or 89 centimeters, of rain. That amount is considered sufficient to loosen steep slopes where some of the island's 210,000 residents live off the grid in improvised housing.

The National Hurricane Center predicted 8 to 12 inches, or 20.3 to 30.5 centimeters, of total rainfall across Maui and the lower elevations of the Big Island, and 4 to 6 inches, or 10.2 to 15.2 centimeters, across the broader island chain.

As the hurricane approached, shelters were opened, public events were canceled, and ranchers were urged to leave their cattle in open pastures rather than in structures that might collapse. Many residents are still dealing with the aftermath of devastating floods that struck in March and were taking additional precautions.

Bobby Camara, a 75-year-old lifelong resident, said he planned to "hunker down, cross my fingers, hope the lights don't go out" at a care home just outside Hilo. He noted that gas stations were busy as people sought fuel for chain saws and vehicles.

"I think stocking up is part of life over here. ... You learn to be self-reliant," Camara said.

Mike Caputo, a 50-year-old local fire captain living in Keaau, near the Big Island's east coast, said his power generator was ready and a 10,000-gallon home water tank was full. His main concern was flash flooding and fallen trees, particularly albizia, a species common to the area.

"They're not very sturdy, but they grow extremely large," Caputo said. "They can make roads impassable."

Christine Matsuda, a resident of Waimea on the northern side of the island, described conditions during the storm.

"Big gusts every few minutes rattle the whole house," she said. "We're finding unexpected leaks in places that don't see water under normal conditions."