Jack Gregg

High tide at Pier 14 in San Francisco during the winter of 2011.

No one knows exactly how much sea level rise the San Francisco Bay Area can expect from climate change, but king tides — extremely high seasonal tides — may give insight into what could be normal in the future.

Starting today and continuing through Sunday, king tides are expected in the morning hours around the Bay Area. Recent rainstorms and the accompanying runoff will likely make these tides even bigger. The California King Tides Initiative is again asking for citizens to document the visual effects of king tides and add them to a Flickr photo pool to help give a perspective on how sea level rise might change local landscapes.

Sea levels have risen about eight inches in the last century and the San Francisco Bay Conservation & Development Commission (BCDC) has warned that the area should be ready for 16 inches of sea level rise by mid-century.

Waves slosh on to San Francisco's Embarcadero during Thursday's "king tide" (Photo: Gretchen Weber)

Take naturally-occurring extremely high tides, and add to them high winds and torrential rain, and you get some pretty big seas.

At least, that’s what I got out on the San Francisco Bay today.  How big exactly, is hard to say (our uneducated guessed ran the gamut), but they were big enough to wash over the bow of our 26-foot boat on more than one occasion and to keep most of us aboard holding on for dear life for much of the three-hour voyage.   What I can say for sure is that as I type this blog post, four hours later, my body still feels like I’m rolling up and down and back and forth on some stormy seas.

We braved the weather today to check out the latest round of “king tides” and see how they affect low-lying shorelines in places like Crissy Field, Treasure Island, and SFO. The seas were so rough that we didn’t make it all the way to the airport, but we did see waves crashing over the sea wall along the Embarcadero  just south of the Ferry Building (see video below). At Crissy Field, the beach was nearly submerged and a small footbridge near the mouth of the estuary was almost awash.

“We think this is indicative of what a normal high tide will be as we start to see the effects of sea level rise in the coming decades,” said Jason Flanders, a staff attorney for San Francisco Baykeeper, the organization that supplied the boat for the white-knuckle outing.

Sea levels in the Bay Area have risen about eight inches over the last century, and officials are planning for an additional rise of 16 inches by 2050 and 55 inches by the end of the century.

“Our shorelines are constantly shifting, as a result of high tides and as a result of sea level rise, which we’re already experiencing,” said NOAA coastal fellow Heidi Nutters, who was also on the boat. “Coming out on day like today, you can get a sense of what our shorelines will look like in the future.”

Nutters is part of a new effort called the Bay Area King Tide Photo Initiative, which aims to encourage members of the public to document extreme high tides by taking photos and sharing them online.

“The more folks that go out and take pictures, the better record we have of how these high tides affect our different communities,” said Nutters. “The tides affect different places differently, and we need as much evidence as possible.”

There are other efforts to document king tides on the west coast, including one in San Diego.

I shot this video from the boat, just south of San Francisco’s Ferry Building. You can see the waves sloshing over the sea wall onto the Embarcadero (Warning, watching this just might make you a little sea sick.)

High tide at Pier 14 in San Francisco on January 19, 2011 (Photo: Jack Gregg)

This week another round of extremely high tides will hit the California coast, providing a glimpse of what the state can expect as sea levels continue to rise. These “king tides” will roll in from February 16th through the 18th, with the highest swells expected on the morning of the 17th, between 7:30 and 9 a.m.

A consortium of environmental groups is again calling for help documenting these high tides. The San Francisco Bay National Estuarine Reserve (NERR), which is spearheading the local effort, has set up a Flickr site where members of public can share their photos.  Organizers launched the site last month, in time for the king tides in January, and since then more than 80 photos have been uploaded by dozens of contributors.

“It’s exploded,” said Bobak Talebi, who is managing the Bay Area King Tides Photo Initiative for NERR. “It’s been great.  We’ve been gaining interest from the general public and from new organizations.  It’s more than we expected.”

Talebi said partnerships with a similar effort in San Diego and a new statewide effort will provide the building blocks to expand documentation of high tides.

Sara Aminzadeh of the California Coastkeeper Alliance says king tides are an important reminder of just how vulnerable many shoreline developments are to sea level rise and storm surges.

“Climate change and sea level rise are such huge issues and they are going to occur slowly, so they can be hard for people grasp,” she said, “but this project can really help people visualize what we’re facing as Californians.”

High tides this week are likely to be higher than they were for January’s king tides, said Talebi.  At that time, the weather was calm.  This week, rain and winds are expected, which will likely exacerbate high tides.   A “Hazardous Weather Outlook” for the Bay Area from the National Weather Service says large swells arriving Wednesday will coincide with the king tides, producing breakers up to 15 feet and possible minor coastal flooding.  Which, of course, is just the kind of scenario that could likely become more common as sea levels rise.

Aminzadeh is hoping that heightened public interest in the Photo Initiative specifically, and in sea level rise in general, will influence the state’s Ocean Protection Council (OPC) to make strong recommendations for sea level rise adaptation planning.  The OPC is an inter-governmental body tasked with coordinating ocean-related state efforts.  It’s scheduled to release its second draft resolution on sea level rise next week.

The Alliance, along with several other environmental groups including the Natural Resources Defense Council and the Sierra Club, are urging the OPC to adopt a resolution that not only sets projections for what sea level rise will look like, but also sets clear guidelines for how state agencies and municipal governments should deal with it, in accordance with principles from the 2009 California Climate Adaptation Strategy.

“We’re looking to them to take a leadership role on how agencies and communities can begin addressing sea level rise,” said Aminzadeh.

Sea levels have risen about eight inches in the last century, and the San Francisco Bay Conservation & Development Commission (BCDC) advises planners to prepare for a sea level rise of about 16 inches by mid-century and 55 inches by 2100.