After a few hundred digiscoped pics (and a few w/ the 300/2.8 VRII and Nikon D7100) the skies opened up and I was soon enveloped in a downpour. I decided it was a good time to back away and allow the bird to return to its bit of shelter next to the pipe. I would ride back to the car through a downpour and muddy trails thoroughly drenched, but happy.
While reviewing images of the bird I tried to determine if it was a male or female. Most recent literature suggests that sexing owls in the field is now risky since its possible to see all-white females when all-white birds were considered males. Still, I checked the Cornell Website for some ID tips and decided to use extent of bib and broken barring on the tail to call my bird a male. Some brown feathering along the edges of the flight feathers suggest that it may be a sub-adult bird, but am only speculating.
Other references include Josephson (1980) and McMorris (2011), which are worth a good read!