Predicted Extreme High Tides for California: 1983–2000

Abstract

When a combination of high tides and severe storm induced waves devastated California's coast in the winter of 1982-1983, predictions of much higher tides in the early 1990's appeared in the press. Standard harmonic tide predictions are prepared for San Diego, Los Angeles, San Francisco and Humboldt Bay extending until the year 2000. These show that the range between annual extremes at any station is only 0.4 foot (0.12m) with the highest tides predicted during the period 1986-1990. The predictions include: The semiannual beat of tide constituents which produce peak tides each summer and winter; a distinct 4.4 year beating which peaked during 1982-1983; and a peak enhancement of extreme tides in 1987 from maximum contributions of diurnal constituents due to the 18.61 year cycle in the longitude of the moon's node. Future astronomical components of extreme tides will exceed those of 1982-1983 by at most several tenths of a foot.