An undersea volcano that erupted Saturday near the Pacific nation of Tonga sent a surge of waves into the Santa Cruz Harbor about 70 miles south of San Francisco.
Lifeguards on personal watercraft sped out of the Santa Cruz Small Craft Harbor to help a vessel in distress in the Monterey Bay off the coast of Capitola as tsunami surges battered the Santa Cruz County coastline.
Crowds gathered at the harbor to watch the rising and falling water strain boat ties on docks. Law enforcement tried to clear people away when big surges started around 7:30 a.m.
About an hour later, a surge went over the back lip of the harbor, filling a parking lot and low-lying streets and setting some cars afloat.
Elsewhere, two people were taken to the hospital after being swept out to sea while they were fishing at San Gregorio State Beach in San Mateo County, Cal Fire said.
Waves reached the front of the Santa Cruz Beach Boardwalk. People also went to Lighthouse Point in Santa Cruz to watch the large waves.
Although experienced surfers would consider the waves reaching the West Coast barely high enough to qualify as swells, the National Weather Service warned that tsunamis cause deceptive water surges powerful enough to pull people out to sea.