← Coast Conditions

Guide

Small craft advisories and the marine zones

Checked September 17, 2026 against the National Weather Service.

The Marine tile repeats the National Weather Service’s forecast for the strip of water your town opens onto. This page explains which zone that is, what the advisories and warnings mean in numbers, and the one line in the forecast that is most often misread.

Two offices, and a line at Point St. George

Almost all of this coast is forecast by the National Weather Service office in Eureka. The exception is the water north of Point St. George, just above Crescent City: that zone runs north across the state line and is forecast by the Medford office. So Fort Dick and the Smith River read a different office’s forecast from Crescent City, a few miles away.

The other line that matters is Cape Mendocino. Everything from Point St. George down to the cape is one zone; the Lost Coast south of it, Petrolia and Shelter Cove, is the next.

The zones, and the ten-mile line

Each stretch is split in two: an inner zone out 10 nautical miles, and an outer zone from 10 to 60, between the same headlands. The inner zone is the one that matters for the surf, the bar and a small boat, and it is the one the board shows.

ZoneBetweenOfficeTowns on this board
PZZ356North of Point St. George, out 10 nmMedfordFort Dick
PZZ450Point St. George to Cape Mendocino, out 10 nmEurekaCrescent City, Orick, Trinidad, McKinleyville, Arcata, Manila, Samoa, Eureka, King Salmon, Fields Landing, Loleta, Ferndale, Fortuna
PZZ455Cape Mendocino to Point Arena, out 10 nmEurekaPetrolia, Shelter Cove
PZZ410Humboldt Bay BarEureka
PZZ415Humboldt BayEureka

The outer zones are PZZ470 off Point St. George to Cape Mendocino and PZZ475 south of the cape.

Humboldt Bay has zones of its own

Since April 2, 2019 the weather service has split Humboldt Bay into two zones: PZZ410, the Humboldt Bay Bar, cut down to “only the immediate harbor entrance (bar channel)”, and PZZ415, Humboldt Bay, the bay inside it. The bar gets its own zone because a bar behaves like nothing else nearby.

Those two zones are where an advisory or warning for the bay itself is posted, but the regular coastal waters forecast has no written section for either of them. For the entrance the Eureka office publishes a separate Humboldt Bay Entrance Channel Forecast, and cautions that “ongoing shoaling of the entrance to Humboldt Bay can impact the accuracy” of it. The Bar conditions tile is the Coast Guard’s report of what the entrance is doing now; the forecast is what it is expected to do.

What the words mean, in knots

These are thresholds, not moods. The National Weather Service publishes them:

The line most often misread

A forecast of “seas 10 feet” does not mean the waves are ten feet. Seas means significant wave height: “the mean or average height of the highest one third of all waves.” Two thirds of the waves are smaller than the number. Some are very much larger.

“Be aware that wave forecasts are an average. The height of some individual waves can be expected to be as much as two times greater. Reports of ‘rogue’ waves of even greater heights are not uncommon.”

So a ten-foot forecast is a forecast that includes twenty-foot waves. Read the number that way every time.

On the beach, not just on the water

The same swell makes the hazard people on this coast are most often caught by. The Eureka office’s beach safety brochure: “Sneaker waves can strike without warning. Sneaker waves surge high up on the sand with enough force to knock you down and drag you into the ocean.” Nationally, the service says they can run up the beach by at least 150 feet.

The same brochure says three to five people drown on the north coast each year to sneaker waves, cold water, or going into the ocean after a dog. Stay farther back than feels necessary, stay off logs at the water’s edge, and “never turn your back on the ocean.”

Sources