Bay Area to see highest King Tides in 18 years this winter

The Bay Area, including San Jose, is expected to experience the highest King Tides in 18 years this fall and winter, CBS News Bay Area reported. These tides occur annually but this year’s are predicted to be notably higher due to several aligned factors.

King Tides happen when the sun and moon’s gravitational pull on Earth is strongest, typically during new or full moons when Earth, sun, and moon are aligned. Additionally, the moon’s closest approach to Earth, called perigee, occurs about every 28 days and intensifies the tides. This winter, these conditions coincide with Earth’s closest orbit to the sun, amplifying the tidal heights.

A longer 18.6-year lunar cycle is currently in its phase that stretches tidal ranges, causing higher high tides and lower low tides. This cycle, combined with a strong El Niño and a marine heatwave warming California’s coastal waters, leads to thermal expansion where warmer water takes up more space, further raising tide levels.

Climate change has also contributed to baseline sea levels rising by at least 8 inches over the past century, adding to the elevated water levels during King Tides. In San Francisco, the highest recorded tide was 8 feet in 1983, and this December’s King Tides are predicted to reach about 7.33 feet, which is near record levels.