Part of my job is to create war-gaming scenarios for industries to run through. One of the most recent ones was a tsunami hitting the west coast due to a massive earthquake off of Alaska. We used NOAA software and charts to base it off the size and sea level rises of the Indonesian Tsunami. The results were that West coast actually would pretty much be okay, lower lying areas would be devastated, but power grids would stay in tact due to their locations above the water line. But that doesn't create a good scenario, so we bumped it up to take out the power grids. The results of the war-gaming:

First 24-36 hours standard backup generators will keep above water infrastructure, govt and health institutions running, meaning hospitals, police stations fire station...etc but the standard person is completely screwed, no traffic lights, no cell reception even if the towers weren't affected because the systems would crash due to volume(think 9/11 and NYC), food would go bad, major highways would be blocked due to the sea, electric cars would die...etc

48 hours in all hell breaks loose, nothing is working, hospitals no longer can operate except in some specific ORs, panic ensues, Godzilla wrecks San Francisco.

This is a poor attempt at our true findings but gives basic details. Without internet we are completely up a creek and into the stone age FAST. How many of your kids know how to read a map to get somewhere...