Here's a photo I took with annotations of the Reid (the green line).
If you click on the link below, it'll take you to where you can link to photos at the numbered points. Berg is between point one and two and like EB said is the only crevasse over there I've ever seen in probably 8 to 10 climbs there.
http://www.summitpost.org/west-side-routes-annotated/203354/c-764768