California tsunami: Here's where damage and casualties could be the worst

Tsunamis pose a risk to the entire California coast. But should a major one strike, how bad could it be?

A single tsunami likely won't cause the worst-case scenario for every region. But in total, more than 680,000 Californians are in a tsunami hazard area during the daytime. And in all, $12.6 billion in damage is possible across California's 20 coastal and bayside counties—a figure that doesn't include damage to ports, harbors, roads, essential facilities or other infrastructure.

There are two main types of scenarios for a tsunami. The first, a "distant-source" tsunami, comes from far away, like one spawned by a major earthquake in Alaska. That would provide an extensive warning—six hours for L.A. and five hours for San Francisco—but could produce the highest level of inundation for large swaths of the state.

Then there are "near-source" tsunamis, which can wash ashore in as little as 10 minutes following a nearby earthquake—leaving little time for a notice or evacuation.

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