King tide event to hit Santa Cruz coastline over weekend

SANTA CRUZ — Santa Cruz County waters will likely be pulled to a biannual peak over the weekend, with the arrival of a “King Tide” event.

The National Oceanic and Atmospheric Administration predicts ocean tides will reach a high mark of around 6.7 feet at Santa Cruz beaches through Sunday.

That peak though, isn’t much more than a high tide Santa Cruzans might see any other given day, said Gary Griggs, who studies sea-level rise and coastal erosion at UC Santa Cruz.

“It sounds like a tsunami coming but if you look at the actual magnitude, it’s a few tenths of a foot higher than the other tides during the year,” Griggs said.

Onlookers might be able to spot the difference at gently sloped beaches, such as Main Beach or in the Capitola area, according to Griggs. King tide forces also pull those high waters back farther than usual, revealing stretches of coastline and rocky nooks otherwise not seen.

The king tide phenomenon, Griggs explained, is largely celestial.

Every day, the world’s ocean waters are influenced by the gravitational pull of the moon and sun, as the earth rotates, triggering high and low tides. But when the earth is at its shortest distance from the moon — and those two together are at their closest point to the sun — gravitational waves amplify.

“When the earth and the moon and the sun are all lined up, we get the highest and the lowest extremes,” Griggs said.

This alignment only happens a couple of times per year, and triggers King Tide events.

While wave-watchers should take caution, the “minus tide” phenomena associated with the event also means ripe opportunities for tide pooling.

Try setting out around 4 p.m. on Saturday and Sunday, when Santa Cruz waters are predicted to be at around -1.6 feet. Griggs suggested Natural Bridges as a place to carefully scour the rocks for sea creatures.

The event will be more dramatic in the San Francisco Bay, where the National Weather Service has issued a coastal flooding alert. Still, Griggs said onlookers should be careful, citing multiple deaths that occurred across the Santa Cruz region this year due to people being swept out to sea.

King tides also give scientists a clue as to what sea levels may look like more regularly in the face of climate change, and rising seas.

“King tides give us some insight into what a higher sea level would look like maybe 10 years in the future,” Griggs said, “As scientists it means we can see that in one day; we don’t have to imagine it.”

By as soon as the year 2030, California could see half a foot of sea level rise, according to an August 2020 report published by California’s Legislative Analyst’s Office. A 2017 report authored by Griggs and other scientists, estimated that if no serious mitigation efforts are taken in the San Francisco Bay Area against sea level rise, the region could experience 1.6 to 3.4 feet of sea level rise by the year 2100.

Interested residents can also submit photos of what king tides look like in their neighborhood to an ongoing California Coastal Commission community science project, that aims to visualize future sea level rise. For information on the project, visit coastal.ca.gov/kingtides.