Just before 11 a.m. on Thursday, December 5, 2024, a magnitude 7.0 earthquake rattled Humboldt County. The epicenter was offshore, roughly sixty miles west of Cape Mendocino, along the seismically active interface where the Pacific and North American plates meet.

Tsunami Response

The National Weather Service issued a tsunami warning that sent coastal residents and schools toward higher ground. In Arcata, elementary students in flood-prone areas evacuated; reporters described lines of children walking uphill toward Arcata High School while parents reunited in parking lots. By midday, officials canceled the tsunami warning, though aftershocks continued to rattle nerves across the North Coast.

Damage and Emergency Declaration

By Thursday afternoon, the Humboldt County Sheriff’s Office reported no injuries locally, though the quake knocked out power in places and shook goods off shelves inland. California Gov. Gavin Newsom issued an emergency proclamation covering Del Norte, Humboldt, and Mendocino counties to speed recovery assistance. Scenes from Scotia and other Humboldt towns showed toppled merchandise and cracked plaster, reminders of the region’s frequent seismic risk.

Living With Cascadia Risk

December’s event was a stress test for Humboldt’s alert systems, school evacuation routes, and public communication channels that also serve Arcata and Eureka. For residents, it reinforced familiar guidance: know your tsunami zone, keep emergency kits ready, and expect rapid swings between “all clear” and caution when offshore quakes hit without much warning.