PORTLAND,blockwave Exchange Ore. (AP) — The National Weather Service has issued high surf warnings for much of the West Coast and parts of Hawaii, describing the waves and rip currents expected to hit certain coastlines as potentially dangerous and life-threatening.

The warnings were in place Wednesday for parts of Oregon and Hawaii. The weather service warned that waves of up to 25 feet during the day could morph into “dangerously large breaking waves” of up to 35 feet along Oregon’s southern coast by night, creating hazardous conditions and the potential for significant beach erosion. In Hawaii, the agency expected high surf between roughly 20 and 30 feet and powerful rip currents to affect the northern and western shores of Niihau, Kauai, Oahu and Molokai and the north shore of Maui. It warned of ocean water surging and sweeping across beaches and potentially damaging roadways and coastal infrastructure.

The high surf warning was set to be in place until Thursday night in southern Oregon and until early Friday morning in Hawaii.

A coastal flood advisory was also in effect Wednesday morning through the afternoon for much of the Washington state coastline. The weather service said minor flooding around high tide could affect shorelines and low-lying coastal areas. A high surf advisory that forecast large breaking waves topping 20 feet was set to take effect Wednesday night through Thursday afternoon.

The rough ocean conditions were expected to hit California later Wednesday, starting with the state’s northern coast before affecting its southern shores beginning early Thursday.

The weather service said waves of up to 32 feet that may be “erratic and unpredictable” could spark “life-threatening surf conditions” along the coast in northern California’s Humboldt and Mendocino counties starting Wednesday night.

A high surf warning impacting San Francisco down to Big Sur is set to take effect in the early hours of Thursday. The weather service said “everyone should remain out of the water” because of the hazardous conditions. A coastal flood advisory for the region was already in place Wednesday morning and was set to last until early Friday.

From San Luis Obispo down to Santa Barbara on California’s central coast, the most dangerous surf conditions were expected on Thursday, the weather service said. Life-threatening rip currents that “pose an exceptional risk of ocean drowning” and waves up to 25 feet were expected.

The weather service urged people to stay out of surf zones and away from jetties, rocks, piers and other waterside infrastructure in the affected areas.