Surface Motion
W hen Waves Hit the River Mouth Cliffs
It's hard to believe that waves used to hit the cliffs at Seabright Beach near the San Lorenzo River Mouth. A natural bridge from this pre harbor wave action can still be seen today.
Seabright Beach cliffs in storm of 1925
Photo by Dorothy Miller
From California Geology, Apr. 1979
The cliffs formed a point that used to project into the surf. This was called Pt. San Lorenzo and formed a point break, which generally was a lesser point break than the breaks at Pt. Santa Cruz but under certain conditions could be a major point break. There is evidence that large sand bars were formed in storm events such as 1925 and 1955, or any year that heavy rains brought excessive silt down the river.
During this era, sandbars that formed at the Rivermouth made long right waves. There is a reference to this in the Rivermouth Sandbar of '82 article.
In a 1925 photo by Dorothy Miller, waves crash against the point and nearby cliffs and threaten a home which lies across East Cliff Drive from the site of the present Santa Cruz Museum.
Seabright Beach in 1976
Photo by Ann Carlson
From California Geology, Apr. 1979
The same house can be seen in a 1976 photo by Ann Carlson. Sand had by then piled up behind the harbor jetty. The beach is then wide and the surf is at least a hundred yards away.
