Your geographic area plus the photos suggest two possibilities to me. One is a washed out specimen of A. flavoconia; the other is A. elongata. To me the combination of a yellow, non-striate cap with yellow volva and an entirely white stem usually means that a guess of A. elongata in the field has a pretty good probability of being confirmed by the narrowness of the spores in the lab. If you feel the specimen was not a washed out or faded specimen, then I’d suggest elongata. A brief description of elongata can be found on the Amanita Studies site (google: Tulloss Amanita elongata).

Very best,

R.