The worst will be the destruction of transportation lines. Rail lines will be ruined, and the highways totally disrupted. I think that I will begin keeping 10 gallons of water in the car at all times, just in case. I live 1/4 west of I-5 and East of Aberdeen, WA.
Parts between the coast and the Cascades appear to only get a fraction of an inch of rain per month during the summer. Is that your seasonal experience?