Like others, I was thinking that the behavior of the critter was more like a
Groundsquirrel, and was thinking Columbia Groundsquirrel based upon colour.
But of course, the area seems out of range for them as well as the sriped
mountain dwellers. I do not think that they occur west of the Cascades. Out
of range for California Groundsquirrel as well and the tail would be too
large in this species from the description given.

Young Yellow-bellied Marmots would be the right size, but again, way out of
range for this species as well.
A good puzzler.

Rick Howie
Kamloops, BC
rick.howie at shaw.ca