Conditions aligning for Bay Area to expect highest King Tides in 18 years – CBS News

Conditions aligning for Bay Area to expect highest King Tides in 18 years  CBS News

King tides bring coastal flooding to the Bay Area every winter. But this fall and winter, the region is expected to see the highest tides in 18 years. Why does this year have the potential for near all-time high water levels? It's the combination of a few things, not only El Niño. First, tides are caused by the sun and moon's gravitational pull on Earth. Earth reaches its closest orbit to the sun in early January, which means the sun has a slightly stronger pull on our tides in the winter. During full or new moons — which occur when the Earth, sun, and moon are in alignment — tides are slightly higher.

But once about every 28 days, the moon reaches a 'perigee,' its closest point of approach to the Earth. This is the point at which the gravitational pull of the moon is strongest, so a new or full moon in the winter, when the moon is closest to Earth and the Earth is closest to the sun, normally creates the highest tides of the year, also known as King Tides. The Bay Area sees these every year. But there's also a slow wobble in the tilt of the moon's orbital plane relative to Earth's equator that cycles every 18.6 years. During the first half of the cycle,