Another round of extra-high tides, known as king tides, is scheduled to roll up onto Bay Area shores this week and a civic group is asking citizens to help with photographing the phenomenon.
King tides are normal, but are the winter's highest tides, caused when the moon, earth and sun are aligned in a way that creates the greatest gravitational pull on the earth's seas. That alignment occurs when the moon is at its closest orbital point to the earth and the planet is at its closest point to the sun.
The last round of king tides came to shore Dec. 30 through Jan. 2, and the current set, the last of the season, will be seen Wednesday through Friday.
The California King Tides Initiative, a coalition of state and federal agencies and nonprofit groups, is inviting Bay Area residents to photograph the ultra-high tides and contribute the images to a website.
The purpose is to provide a record to help Californians envision the possible future impact of rising sea levels that may be caused by global warming.
"The big, big goal is to get people to start thinking about coastal change, especially as it relates to sea level change," said Sara Aminzadeh, executive director of California Coastkeeper Alliance.
The alliance is one of the participants in the initiative, along with the California Coastal Commission, the San Francisco Bay Conservation and Development Commission and the San Francisco Bay National Estuarine Research Reserve.
Photos can be uploaded to the initiative's flickr site at http://www.flickr.com/groups/cakingtides/.
In addition, the group is joining with the U.S. Geological Survey to collect photos of specific locations during the king tides for use in research.
The research is aimed at identifying which areas are most at risk of flooding and future rises in sea level. Researchers will compare the photos contributed to the collection with computer simulations of flooding to see how well the simulations match reality.
To learn more about the project and to choose a location to photograph, visit http://california.kingtides.net/when/our-coast-our-future/.
Several Bay Area environmental groups are sponsoring king tides walks.
The San Francisco Exploratorium and the King Tides Initiative are offering a photodocumentary walk along the San Francisco shore of the bay on Wednesday, beginning at 9 a.m. at the Wave Organ at 83 Marina Green Drive.
For more information, go to http://california.kingtides.net/2014/01/26/snap-the-tides-with-the-exploratorium-on-jan-29/.
Watershed groups in a coalition called Friends of Five Creeks are sponsoring walks along the Berkeley watershed at 9 a.m. Thursday; at the Oakland estuary at 10 a.m. Thursday; along the Palo Alto Baylands at noon on Thursday; and along Gallinas Creek in San Rafael at 11 a.m. Friday.
Details can be found at http://california.kingtides.net/2014/01/06/friends-of-five-creeks-will-offer-king-tides-walks-jan-29-30/.