The largest swell of the season is here, with an expected peak Wednesday that brought surf up to 45 feet to Hawaii’s north shores.

The National Weather Serv­ice has issued a high-surf warning covering the north- and west-facing shores of Niihau, Kauai, Oahu, and Molokai; the north-facing shores of Maui; and the west-facing shores of Hawaii island through 6 p.m. today.

Forecasters expected the northwest swell to build down the island chain and peak Wednesday, then gradually lower today.

Officials say the public should stay away from the shoreline along affected coasts and postpone entering or leaving channels affected by the high surf.

The weather service said Wednesday afternoon that surf is expected to reach 35-45 feet along north-facing shores and 20-25 feet along west-facing shores of smaller islands. On the west-facing shores of Hawaii island, surf is expected to be 8-12 feet.

In addition to powerful rip currents, ocean water is expected to surge and sweep across beaches, periodically overtopping vulnerable coastal roadways, with localized beach erosion.

Wave run-up also is expected to affect coastal properties and infrastructure, especially around high tide just before daybreak.

Honolulu lifeguards were busy due to the high surf. Ocean Safety said lifeguards rescued five people from North Shore waters Wednesday and took 2,260 preventive actions. Of all beaches, Waimea Bay was the busiest, with crowds on shore and surfers in the lineup.

On the west side, Ocean Safety lifeguards rescued 35 people and took 1,065 preventive actions. The majority of rescues on the west side were at Makaha Beach, officials said, where there was a large crowd of surfers.

In one instance, lifeguards rescued a 40-year-old road worker who was injured along Kamehameha Highway near the Rock Piles surf spot when a large wave hit roadside barriers.

Ocean Safety responded to five people in trouble at Ko Olina lagoon No. 4. Two young children, both wearing life jackets, were playing in shallow water when a rogue wave entered the lagoon through the opening, pulling them out into the open ocean.

Three adult men — relatives of the girls — entered the water to rescue them. All five were able to get back to shore on their own.

Paramedics treated the adults for lacerations. They declined transport to a hospital, but one man drove himself to an emergency room for further medical treatment. The two girls were uninjured.

In addition to the high-surf warning, a high-surf advisory is in place for the west-facing shores of Maui and Lanai, and the north-facing shores of Hawaii island due to the swell, also through 6 p.m. today. On Maui and Lanai, surf is expected to be 10-14 feet; on Hawaii island, expected surf is 18-22 feet.

Strong, breaking waves and currents in these areas will make swimming dangerous through this evening. The public should heed all advice from Ocean Safety officials.

A small-craft advisory is also in effect for all coastal waters and in windier areas of Maui County and Hawaii island. The advisory is in effect through 6 p.m. today.