On Wednesday, 15 November 2006, Crescent City Harbor, in Del Norte County, Calif., was hit by surges resulting from the tsunami generated by the Mw= 8.3 Kuril Islands earthquake. The strong currents caused an estimated US $700,000 to $1 million in losses to the small boat basin at Citizen's Dock, destroying or damaging three floating docks and causing minor damage to several boats (Figure l).The event highlighted a persistent problem for tsunami hazard mitigation: Most people are still unaware that the first tsunami waves rarely are the largest and that the potential for damaging waves may last for many hours.