UPDATE 12:25 a.m., 7/22/20 — A new message from the NWS says there is no threat to California.
WILLITS, 7/21/20 — A magnitude 7.8* quake off the southern coast of Alaska has triggered a tsunami warning for that area, however at present, as of 11:41 p.m., there is no warning for California, Oregon, or Washington.
The tsunami warning covers the Alaskan Peninsula, up through the Cook Inlet, and some of the Aleutians. According to Tsunami.gov, there is no such warning for the West Coast, but confirmation may depend on getting more details information.
Large earthquakes at sea do not always automatically result in tsunami. Conditions on the seafloor, as well as the kind of quake and the depth of the quake mean that quakes of similar official magnitude can feel very different or have very different results — a phenomenon we are all very familiar with here in Californai.
We will continue to update as more information comes in.
We a tsunami to strike California, it would no likely cause significant harm to coastal towns in Mendocino, which mostly sit on bluffs above the sea, however, the harbors and docks could see some damage.
*Note: The quake was initially listed as a 7.4 and has been upgraded to 7.8.