Hurricane Lala weakened to a tropical storm Sunday after skirting Hawaii without making landfall, but it wasn’t done punishing the Big Island with hurricane-force gusts. Total rainfall of nearly three feet (one meter) was expected on the higher windward slopes, turning rivers into raging torrents and threatening mudslides.

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

Powerful waves pounded the Big Island’s coast as Lala slowly passed by. Howling winds whipped palm trees and waterways swelled with fast-moving runoff from relentless rain that blew nearly sideways.

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, while 19 roofs were lost in the “enormous storm,” the governor said Saturday evening. “There have been a lot of roads impacted, our crews have already been out to more than 30 sites.”

A search-and-rescue mission including Civil Defense, the National Guard and 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 said 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.

What’s next for Lala

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

As of 2 a.m. Sunday in Hawaii, Lala was centered about 105 miles (170 kilometers) west-northwest of Kailua-Kona and about 100 miles (160 kilometers) south of Honolulu, with tropical-storm-force winds extending as much as 175 miles (280 km) from its center.