Port Townsend, Jefferson County, Washington, USA September 2, 2008
Based on the very helpful GUIDE TO THE BOMBUS OF SAN FRANCISCO By Quinn S. McFrederick (http://online.sfsu.edu/~beeplot/pdfs/San%20Francisco%20Bombus.pdf), this is a male Bombus vosnesenskii of type b in the illustrations. Note the partial second light-colored band on the abdomen.