There will by an high probability of sneaker waves on local beaches on Thursday and Friday, according to local National Weather Service forecasters. Sneaker waves, as explained in greater detail below, are those sudden and unexpected large breakers that surge up onto the shore at long intervals, catching beachgoers by surprise.
Side note: You may not know that the science of predicting sneaker waves was developed right here in Humboldt County, by local NWS forecasters. Check out this cool writeup on LiveScience.com.
Says the National Weather Service:
There will be a moderate risk of sneaker waves on Northwest California beaches Thursday and Friday as a long period swell builds into the waters. Sneaker waves are larger waves that seem to come out of nowhere and run farther up the beach slope than normal.
Sneaker waves can catch you off guard and quickly pull you into the ocean where survival is unlikely because of strong currents, turbulent surf, and very cold water. Do not be fooled by an ocean that looks calm. There can be up to 20 minutes of small waves right before a sneaker wave strikes. Avoid steep beaches, rocks, and jetties. Stay far back from the surf and do not go in after dogs that get pulled into the surf.
Dogs almost always get out on their own.