King Tide flooding on SF waterfront foreshadows future climate change norm – CBS San Francisco

SAN FRANCISCO (KPIX) — The royal tide returned to the Bay Area, peaking Saturday morning.

“Well, you think you’re looking at something you see every day and all of a sudden your feet get wet and it’s not what you see every day – so you back off,” Joy Durighello said. , resident of San Francisco. “It’s an interesting phenomenon for sure.”

She and a group of people witnessed the annual phenomenon at an educational seminar hosted by the Exploratorium at a location between Pier 3 and Pier 5 on the San Francisco waterfront.

So what is the royal tide?

“It’s when we have a new moon or a full moon coupled with a perigee – which is when the moon is closest to us each month – coupled with a perihelion, which is when the earth and the sun are closest during the revolution of the earth around the sun,” explains Lori Lambertson, an educator at the Exploratorium. “This means that we are going to have a high tide higher than usual, as well as low tides lower than usual. usually.”

That is, they occur when the moon, earth, and sun align and the moon is at its closest approach to the earth as the earth swings closest to the sun.

“The normal tidal range for our area — average highest tides and average lowest tides — is about six feet,” Lambertson said. “On a day like today, the water level difference between high tide and low tide will be about eight feet.”

Since it was a relatively calm day, the waves weren’t crashing on most sidewalks or flooding the streets. However, they spilled onto low alleys at various locations along the Embarcadero.

The phenomenon is still infrequent, occurring once or twice a year, but climate change, coupled with sea level rise, is happening. So today’s royal tide is tomorrow’s regular high tide, Lambertson said.

“It’s exciting to see the water come up the sidewalk once or twice at this time of year, but when it starts to happen more frequently, it won’t be exciting anymore,” she said. “It’s going to be a nuisance and it’s going to damage infrastructure and create a lot of problems in our communities.”

If anyone has taken photos or videos of the high tides, the California King Tides Project encourages people to send in their photos so they can better understand what the state will experience as climate change causes the sea level to rise. of the sea.

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