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Waves crashing off the coast of Monterey Bay

A look at what winter storms bring to shore

A close-up of an assortment of mussel shells, snail shells, bleached corraline algae, and rocks washed up on a beach

Story

Feb. 14, 2024

Allen Protasio

What's washed up on the beach?

Winter is an exciting time to explore Monterey Bay’s beaches. Storms passing over the Pacific Ocean combined with seasonally extreme tides can create the ideal conditions for beachcombing. But before you go out adventuring, always remember to be prepared!

Winter storms bring energy to the coast

During winter months, powerful storms sweep across the Pacific Ocean often bringing several days of rain and strong winds to California’s central coast. This driving wind energy also creates ocean swell, generating large waves that crash along the coastline. The pounding surf scours and rips off most anything attached to the rocks, including algae (or seaweed), mussels, and limpets, both above and below the surface of the water.

The shoreline is also affected by water running off the land, as each successive storm sends torrents of rainwater down streams, rivers, and storm drains. Eventually, this muddy rainwater makes its way into the ocean, carrying its accumulated contents along with it, like wood debris and trash.

A large ocean wave breaks onto a small island of rocks, tossing a spray of water behind as it crashes

Winter storms often bring large waves that crash along the Monterey Bay coastline. The pounding surf can rip off animals and algae that were attached to the rocks and wash them ashore.

Winter brings extreme tides

Wintertime is also when we experience the most extreme fluctuation in the tides along the Central Coast. Earth’s tides are influenced by the gravitational pull of the sun and moon, and is generally strongest during new and full moons, when the Earth, moon, and sun are all in alignment.

Because the moon's also generally closest to the Earth in its rotation in winter, we typically see our highest (and in turn, our lowest) tide heights of the year. The changes are most dramatic during king tides, when we experience the greatest difference between the highest high tide and lowest low tide of the day. Sometimes, the tidal exchange can be more than eight feet!

During high tide, much of what’s been churned up by waves and turbulent waters from the storms gets deposited high up on the shoreline. As the water recedes, some of this material remains behind, while the rest gets carried back toward the ocean. Over time, this creates “bathtub rings,” or lines of marine debris and materials on the shore.

A beach landscape at sunset has two dark lines extending along the sand mirroring the shoreline. Upon closer inspection, the lines contain thousands of washed-up mussel and snail shells

High tides bring what’s been churned up underwater and ripped off rocks and deposits them high up on the beach. As the tide recedes, lines of marine debris containing snail and mussel shells are left behind.

What's washed ashore this winter?

These tide lines often contain the treasures we seek while beachcombing. What washes up depends on the combination of weather and tides, but also the nearby underwater environment.

A pair of long-billed curlews forage in the low tide as waves crash further behind them

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You may not be the only one enjoying the bounty on the beaches. Many species of migratory shorebirds stop on Central Coast beaches to take advantage of low tides to snag a sand crab or small clam, or use their long bills to investigate kelp wrack in search of insects.

The bare remains of a whale skull washed up on a beach

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Sometimes, all of the increased ocean energy can wash up some unexpected items, like this whale skull.

A bivalve shell rests open and upside-down on the sand as waves crash in the distance behind

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On stretches of the bay where the beach and adjoining undersea habitats are sandy, you may find sand dollar tests, clam shells, sand crabs, or remnants of other animals that bury themselves in the sand

A beach landscape with stick, twigs, and other wood debris scattered across wet sand

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Near the mouths of rivers, you may find more wood debris that’s washed down from inland forests.

A collection of various mollus shells and corraline algae washed up on a sandy beach with small boulders in the background

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If you’re exploring adjacent to rocky shores, you’ll generally find molluc shells from mussels, snails, and scallops. The strong surges rip them off rocks, and huge amounts can accumulate on the beach.

A beach landscape reveals a small tangled mass of bare, brown kelp strands embedded in the sand. Shoeprints lead past the pile of algae towards a washed-up log in the distance

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You might also find different types of kelp, including giant kelp, bull kelp, and sea palms. Often, the weakened stalks are broken or ripped off, but sometimes you can also find the holdfast that these algae use to anchor themselves to the rocks. Look closely and you’ll find an entire ecosystem contained within!

The white, segmented, flower-like remains of coralline algae rest upon a pile of mussel shells and rocks on a beach

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You can also come across the white, shell-like skeletons of coralline algae – red algaes that build calcium skeletons. All of the dead and dying material becomes essential food for scavengers like beach hoppers – small crustaceans that burrow into the sand and feast on kelp and other organic material at night. The piles of decaying kelp also support beetles, flies, and other insects.

And that’s part of the joy of a beachcombing adventure. You never know what you’ll find!

Come join us for a beach field trip!

Our team visited Sunset State Beach in January 2024 to see what had washed up after a winter storm — look what we found!


Helpful tips for heading to the beach

If you’re interested in checking out what Monterey Bay’s beaches have to offer in the winter, remember to be prepared!

  • Check the weather. A great time to go is during the lull between storm systems.
  • Pay attention to the tides. It’s best to explore during low tide, and be mindful of the rising tide.
  • Be careful. Wear safe footwear and watch where you step. Explore with your eyes and don’t take anything home.
  • Respect the ocean. Never turn your back to the water as waves can be unpredictable.
  • Low tides make this a fantastic time of year to go tidepooling, too. Be sure to check out our tidepooling tips.

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