King Tide Flooding on SF Waterfront Foreshadows Future Climate Change Norm – CBS San Francisco

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

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

She and a group of people took in the yearly 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 king tide?

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

Another way to put it, they occur when the moon, earth and sun come into alignment 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 — from the average highest tides and the average lowest tides — is about six feet,” Lambertson said. “On a day like today, the difference in the water levels from the high tide to the low tide is going to be about eight feet.”

As it was a relatively calm day, waves weren’t crashing onto most sidewalks or flooding streets. However, they did spill onto low-lying walkways at various points along the Embarcadero.

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

“It’s exciting to see the water come up over the sidewalk once or twice at this time of year but, when it starts to happen more frequently, it’s not going to be exciting,” 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 took photos or videos of the high tides, the California King Tides Project is encouraging people to send in their photos so they can increase understanding of what the state will experience as climate change causes sea level to rise.