[Star Traveler]

This image was captured by the GOES 3 satellite on May 18, 1980 at 15:45 UTC (that would be 8:45 local time, which would be 13 minutes after the eruption began).

The diameter of the cloud (from left to right) is about the distance that it is from Portland, Oregon to the beach. And to drive that distance, from Portland to Seaside, takes about 1-1/2 hour. That's how big the eruption cloud is in about 13 minutes.

[Ladysmith]

You’ve made this thread absolutely fascinating with your images and information. Thanks!