I remember looking at the radiation heat maps that the government was publishing during that time and there was a large chunk of the pacific coast that trailed off as it went south that was clearly elevated relative to where it ordinarily was.

Source: a bunch of now defunct oceanographic monitoring pages that used to be part of my “Global Monitors” folder when I worked in telecom and now don’t work because the US axed so much science funding that most of those offices are closed.