Update: Extra-large swell remains above warning levels, causing high surf warning to be extended for Kaua‘i, Ni‘ihau

Update at 6:31 p.m. Nov. 30: Surf generated by the extra-large northwest swell that has been impacting the Hawaiian Islands will remain above warning levels for most north- and west-facing shores through this evening, but will drop throughout the night.

The National Weather Service in Honolulu has extended the high surf warning for northern and western shorelines of Kaua‘i and Ni‘ihau until midnight tonight because of the swell’s persistence, with surf up to 25 feet still expected for north-facing shores and up to 20 feet for west-facing shores.

Strong breaking waves and powerful currents continue to be in the forecast and will continue to make navigating channels dangerous as the warning period continues.

The weather agency again advises the public to stay away from shorelines along the affected coasts, be prepared for road closures and postpone entering or leaving channels affected by the high surf until surf subsides.

For updated information about ocean and weather alerts, visit the National Weather Service website.

Update at 4:12 p.m. Nov. 29: The National Weather Service forecast office in Honolulu has extended the high surf warning in effect for northern and western shores of Kaua‘i and Ni‘ihau until 6 p.m. Saturday as a building extra-large northwest swell will exceed warning levels and peak tonight with monster waves in some areas.

North-facing shorelines are forecast to be bombarded with huge hazardous surf of up to 30 to 40 feet. Surf of up to 25 to 35 feet will crash into west-facing shorelines of both islands.

Surf heights can vary significantly from beach to beach. Surf larger than the upper end of the range provided in the forecast can also occur periodically, sometimes up to a few hours apart.

Expect very strong breaking waves and powerful currents. Breaking waves might make navigating and entering channels dangerous.

The weather agency advises the public to:

• Stay away from the shorelines along the affected coasts.
• Be prepared for road closures.
• Postpone entering or leaving channels affected by the high surf until the surf subsides.

Surf is expected to begin declining during the day Saturday.

Visit the National Weather Service Honolulu forecast office website for updated information about ocean and weather alerts.

Update at 12:13 p.m. Nov. 29: “Largest swell of the season so far will quickly build throughout the day today,” said the National Weather Service forecast office in Honolulu in an email this morning.

The swell referenced is an extra-large northwest swell that triggered the weather agency on Thursday evening in its advance to issue a high surf warning in effect from 6 a.m. today through noon Saturday for north and west shorelines of Kaua‘i and Ni‘ihau because of dangerously large surf the swell is expected to generate.

An updated forecast this morning shows even greater, more menacing, surf heights as the swell continues to fill in today and peaks tonight.

North-facing shores will be pummelled the worst, being crushed already by waves of 20 to 25 feet this morning. The monsters roll in this afternoon and tonight though.

Hazardous waves with at least 30-foot faces — and others reaching up to a frightening 40 feet, with occasional larger sets — will be slamming into northern coastlines.

West-facing shores will fare only slightly better, with surf already at heights of 18 to 22 feet this morning, increasing this afternoon to at least 25 feet and up to 35 feet before the swell peaks later tonight.

The National Weather Service says coastal impacts from the extreme surf along northern and western shorelines are possible, especially during the swell’s peak this afternoon through tonight and the overnight high tide.

Expect ocean water surging and sweeping across beaches, creating the potential for impacts to coastal properties and infrastructure, including roadways.

Wave heights along northern shorelines of Kaua‘i and Ni‘ihau will decrease by Saturday morning, but still be formidable and remain at least at advisory levels.

Surf of 20 to 25 feet is forecast for north-facing shores throughout the morning, then fall to between 15 and 20 feet during the afternoon and evening.

Western shorelines will get the same relief, but warning level surf could linger into Saturday before settling still in advisory territory.

Wave heights of 18 to 24 feet are expected through the morning, with surf of 14 to 18 feet forecast during the afternoon and evening for west-facing shores.

The gradual downward trend will continue, with surf potentially falling below advisory levels by the end of the weekend.

The public is reminded:

• Surf heights can vary significantly from beach to beach.
• Surf larger than the upper end of the range provided in the forecast will occur periodically, sometimes up to a few hours apart.
• Stay away from the shoreline along coasts in the warning areas.
• Be prepared for road closures.
• Postpone entering or leaving channels affected by the high surf until the surf subsides, as breaking waves could make navigating channel entrances dangerous.

“Entering the water in [the warning areas] during the high surf warning is very hazardous and could cause serious injury or death,” said the Kaua’i Fire Department on Thursday evening in a notification about the high surf warning. “Beachgoers are also advised to use extreme caution, as large breaking waves could make it dangerous for those standing along the shoreline.”

For the latest beach hazard and safety information at individual beaches, click here.

Visit the National Weather Service Honolulu forecast office website for updated information about ocean and weather alerts.

For up-to-date information about Kaua‘i ocean conditions and ocean safety, speak to a Kaua‘i County lifeguard at any lifeguard station, click here or call the Kaua‘i County Ocean Safety Bureau at 808-241-4984.

Original post at 6:36 a.m. Nov. 29: A large to extra-large west-northwest swell will drive surf heights up to extreme and dangerous levels through noon Saturday on the northern and western shorelines of Kaua‘i and Ni‘ihau.

Dangerously large peak surf heights of 25 to 35 feet are forecast along shorelines in the warning areas, creating very strong breaking waves and powerful currents.

The public is advised:

• Stay away from the shoreline along coasts in the warning areas.
• Be prepared for road closures.
• Postpone entering or leaving channels affected by the high surf until the surf subsides, as breaking waves could make navigating channel entrances dangerous.

There also is the potential for overtopping of vulnerable coastal roadways and some wave runup to coastal properties near high tide early Saturday morning.

“Entering the water in [the warning areas] during the high surf warning is very hazardous and could cause serious injury or death,” said the Kaua’i Fire Department on Thursday evening in a notification it issued about the high surf warning. “Beachgoers are also advised to use extreme caution, as large breaking waves could make it dangerous for those standing along the shoreline.”

The long-period northwest swell is expected to peak late tonight or early Saturday before gradually declining.

The public is advised to heed all advice from ocean safety officials. If you’re ever in doubt, the best option is don’t go out.

Forecasts from the National Weather Service for other shores around the island show surf along east and northeast shorelines will be remain elevated through the weekend because of a lingering short-period north-northeast swell.

South-facing shores will have near seasonal average surf for the rest of this week, driven by a mix of short-period southeast and background long-period south-southwest swells.

An upward trend is expected this weekend through the first week of December along southern shorelines, however, because of an active pattern developing within the swell window near New Zealand.

Visit the National Weather Service Honolulu forecast office website for updated information about ocean and weather alerts.

For up-to-date information about Kaua‘i ocean conditions and ocean safety, speak to a Kaua‘i County lifeguard at any lifeguard station, click here or call the Kaua‘i County Ocean Safety Bureau at 808-241-4984.