Tidal Memory

Twenty-four columns record twenty-four hours of tide water levels.

Using live data from the NOAA tide station near the Golden Gate Bridge, the twenty-four soaring columns in this exhibit display San Francisco Bay tide heights for the current day. As each hour ends, another column is locked off, preserving the tide height for that particular hour. Visitors can see the rising and falling tidal pattern—and contemplate the significance of the tides.

The tides create strong currents that move nearly one-fourth of the Bay’s total water volume in and out with each tidal cycle. These cycles affect every living thing in the Bay, influencing feeding, breeding, and migratory behaviors.