Swells happen: High surf warning in effect for north- and east-facing shores

Spring has sprung, but swells still happen, and seas are surging this weekend with the arrival of a large north swell today reinforcing a north-northwest swell that built in down the island chain Friday night.

Surf along north- and east-facing shores of most Hawaiian islands — including the Big Island — will become dangerous during the swell’s peak tonight and Sunday after a much larger pulse of the north swell rapidly builds this afternoon.

In anticipation of those surf conditions, the National Weather Service forecast office in Honolulu issued a high surf warning in effect until 6 p.m. April 6 for north and east shorelines.

Strong, breaking waves of 20 to 26 feet are expected by this afternoon along north-facing shores, with breakers of 10 to 15 feet forecast along eastern shorelines.

Powerful currents will accompany warning-level surf, and large breaking waves in channel entrances could make navigation hazardous.

Forecasters advise the public to stay away from shorelines along the affected coasts, be prepared for road closures and postpone entering or leaving channels in the affected areas until the high surf subsides.

Heavy harbor surges also are expected along north-facing harbors such as Hilo Harbor, and a small craft advisory is in place for waters exposed to the north swell.

Hawai‘i County Civil Defense said Friday afternoon that impacted shorelines will include those in North Kohala, Hāmākua, North and South Hilo and Puna.

“Large breaking surf, significant shore break and dangerous currents can cause injury or death,” Civil Defense said in its message.

Emergency management officials advised the public to heed all instructions given by ocean safety officials and to make sure their property along shorelines in the advisory areas is prepared to weather the high surf.

A storm far to the north of the state had an area of high winds pointed mostly south and pushed the large long-period swell toward the islands, according to Harry Durgin, a citizen meteorologist and administrator of the Puna Weather group on Facebook, in a post early Friday morning.

“This swell will be long-lived, beginning late Saturday and holding on through Monday,” wrote Durgin, adding it will not directly hit windward shores, but is centered from a direction best for impacts at places such as Waipiʻo Valley, Richardson Ocean Park in Hilo and Hawaiian Beaches in Puna.

He said surf at those locations and others along the same shorelines could reach 20 feet at times, and with high tide at about noon Sunday, some areas coould see runup over roadways.

Visit the Hawai‘i County Hazard Impact Map for more information about road closures or other hazard information.

Check the National Weather Service statewide surf forecast for the latest surf height forecasts, and visit the Honolulu forecast office website for updated ocean information and weather alerts.