Residents along Northern California’s coast were hastily evacuated and urged to move to higher ground after a magnitude 7 earthquake struck off the coast of Humboldt County, prompting a tsunami warning. The warning, issued just before 11 a.m., advised that a tsunami with powerful waves and currents was possible, but was later cancelled about an hour later.
According to Dave Snider, the tsunami warning coordinator at the National Tsunami Warning Center in Alaska, the initial warning was issued because of the large size and location of the earthquake, which made it necessary to provide residents ample time to reach safety. The team had to verify if a tsunami was forming by monitoring deep ocean buoys and coastal observation stations, which confirmed the warning was necessary.
For the hour that the tsunami warning remained in effect, officials in multiple counties, including Del Norte, Humboldt, Mendocino, Berkeley, and San Francisco, urged coastal residents to evacuate inland. Many people were caught off guard, with some feeling whiplash and others left confused.
In the aftermath, officials determined that a small tsunami, measuring 5 centimeters, did occur in Arena Cove off Mendocino County, highlighting the importance of respecting tsunami warnings and not ignoring them. Snider stressed that being overly prepared is better than being under-prepared, and that tsunamis are quite rare but can have devastating consequences.