Most of the Hawaiian Islands battled high surf today as a strong low-pressure system to the northeast generates a large north swell.

While a high-surf warning for the north and west shores was set to expire at 6 a.m. Friday, surf will remain at advisory levels throughout the day, the National Weather Service said.

Until then, surf of 25 to 30 feet was battering the north shores, with occasional sets of 35 feet on the outer reefs, the agency said. That will drop to 20 to 25 feet Friday.

East shores can expect surf of 10 to 15 feet.

As of 4 p.m. today — Thanksgiving — Oahu lifeguards conducted two rescues and 2,020 preventative actions on the North Shore, and 12 rescues and 1,420 preventative actions on the east shores, according to Emergency Services Department spokeswoman Shayne Enright.

On Hawaii island, Kalanianaole Street in Keaukaha was closed due to high surf and debris on the roadway between Kolea and Oeoe Street, county Civil Defense said. All county beach parks in the Keaukaha area were closed.

And Bayfront Highway in Hilo was closed between Pauahi Street and Waianuenue Avenue due to high surf. Kamehameha Avenue was recommended as an alternate route.

The waves will gradually decline Friday.

Meanwhile, a small craft advisory remains in effect for Hawaiian waters until 6 p.m. Sunday, with strong winds in the channels and seas of 12 to 17 feet Friday. That will drop to 6 to 12 feet Saturday, the weather service said.

Strong and gusty northeast winds will continue across the state through tonight, and possibly through the weekend.Lanai, as well as the leeward Kohala and Kohala mountain areas on the Big Island will experience the strongest winds with gusts possibly reaching 50 mph, the weather service said.