Residents along the Southern California coast can expect the return of perigee spring tides, more commonly known as king tides, on Thursday. These exceptionally high tides occur when the Sun, Moon, and Earth align, increasing the gravitational pull on the ocean tides.
The natural phenomenon is expected to take place on Thursday and Friday and again on January 2 and 3.
The National Weather Service warned California beachgoers Wednesday Stay out of the water due to dangerous swimming conditions, as rip currents can sweep swimmers and surfers into the sea. They also advised staying away from rocks: “Rock jetties can be deadly in such conditions.”
Although massive waves can present dangers to coastal visitors, king tides provide illuminating data on what regular high tide will look like in the coming years as sea levels continue to rise.
By 2050, the mean sea level along the California coast will be is expected to increase up to 1.2 feet and, by 2100, up to 6.6 feet. Climate change is playing a major role in this shift, as a high concentration of carbon dioxide (caused by the burning of fossil fuels) traps heat, melting land glaciers and ocean ice sheets.
Understanding sea level rise and identifying flood-prone locations will inform decisions about the best infrastructure for safer coastal communities.
Here you'll find more information about king tides and how you can safely observe the breaking waves, and even participate in some fun data collection.
What causes a king tide?
King tides occur when the ocean is “pulled” back and forth by the gravitational pull of the moon and sun. These tides usually occur during a new or full moon, causing the oceans to bulge a little more than usual. They are called spring tides “perigee” when they coincide with the moment when the Moon is at “perigee” or its closest approach to the Earth.
King tides are natural and predictable and are not related to climate change.
What is a king tide like?
In simple terms, high tides are higher and low tides are lower than average.
But because these high tides can reach 1 to 2 feet higher than average high tides, they provide insight into the future of sea level rise in the coming decades.
What are the dangers associated with king tides?
A high tide can sweep people out to sea and capsize small boats near shore. High tides can also cause flooding and beach erosion and, in some cases, cliff and cliff collapses.
The NWS beach hazard statement warning visitors to stay out of the water due to hazardous swimming conditions is in effect through Saturday.
The warning includes the coast of Santa Barbara County, the coast of Malibu and the beaches of Los Angeles County. Those areas are expected to experience high tides of 7.2 to 7.8 feet.
In the coastal areas of San Diego County and Orange County, high surf of up to 5 to 6 feet is forecast, and the San Francisco Bay Area has been warned of breaking waves up to 14 feet high.
For more information on tides and currents, visit the National Oceanic and Atmospheric Administration website.
How can I safely observe the king tides?
Despite the dangers associated with king tides, people can safely view this phenomenon (if they take some precautions) from various places along the coast as part of the California King Tides Project.
The initiative is led by the California Coastal Commission to help visualize future sea levels and flood risk in coastal areas. Participants can take a photo during high tide and upload it to a tide mapwhich can then be used by government agencies for research and planning. Scientists can also use these images to better predict future sea levels.
Participants should take extreme caution when walking through slippery areas and stay away from waves. Be aware of local beach conditions.
Some wise and often repeated advice: Never turn your back on the ocean.
