“King tides,” which are about a foot above the average high tides along the San Francisco coast, are hitting the state’s shorelines today through Thursday, and the California King Tides Initiative is encouraging more people to experience the occurrence by taking photos.
Once shared on social media, such images can offer a glimpse into what the future could look like with rising sea levels, according to the group.
“We think these super high tides are kind of an early indication of what we can expect to be the norm,” said San Francisco Baykeeper staff scientist Ian Wren. “And chances are, our existing infrastructure is not equipped to deal with future sea-level rise.”
Last year, several hundred people submitted pictures to www.flickr.com/groups/cakingtides and the initiative’s Facebook page got about 4,000 views, according to Hilary Papendick, coastal program analyst for the California Coastal Commission. For king tides season this December and January, advocates with the initiative would like to see at least 500 photos posted.
In The City, where the average high tide is 6 feet, king tides are expected to be 6.9 feet at 8:59 a.m. Monday morning, 7.1 feet at 9:48 a.m. Tuesday, 7.1 feet at 10:40 a.m. Wednesday and 7 feet at 11:31 a.m. Thursday near Aquatic Park at San Francisco’s tide gauge, the oldest continuously operating tidal observation station in the U.S.
King tide heights and times may vary at other locations in The City and are expected to occur again Jan. 29 through 31. Ultra-high tides also appear in June but are typically not as high and occur at night, when they are more difficult to catch on camera. Storms during king tides can elevate water levels, making flooding worse.
Images from the past couple of years show parts of The Embarcadero, as well as local beaches and wetlands flooded. While sea level has not risen in The City for the past two decades, that will likely change with ocean circulation pattern fluctuations and the average rate is 8 inches per century at the tide gauge, according to Papendick.
Low-lying city infrastructure including San Francisco International Airport, U.S. Highway 101, the Bayview and Hunters Point neighborhoods are at risk of flooding with rising sea levels. The solution for some locations, like SFO, could be building protective walls, while other areas like the 101 may need to be moved inland, Papendick said.
“One of the main things that we can do is identify where there is risk and then plan ahead to help minimize the hazardous situation,” she said. “It can be as simple as raising up a building so that the water goes underneath it, or moving infrastructure back from areas that are flooded.”
The four-year-old California king tide initiative, spearheaded on a voluntary basis by various coastal advocacy groups, branches off a similar effort that originated in Australia.
Clarification: This story was updated Dec. 30 to clarify the impact storms have on king tides.