Specifically, the warning covered the region stretching from the Oregon-California border to Cape Mendocino in Northern California, including Humboldt and Del Norte counties—a red zone where residents were urged to evacuate immediately due to the imminent threat of dangerous waves.

A tsunami warning was issued for California's North Coast, after a massive earthquake off the coast of eastern Russia.

The U.S. Tsunami Warning System ( tsunami.gov) will be updating its guidance as experts learn more about the threat, including maps showing what areas face what risks. In the minutes and hours after a major earthquake, tsunami assessments change as researchers track data from buoy and other interments.