John,
Ever since I started this peak bagging foolishness (Thank you!!) I have been questioning your ranking of the Mt St Helens Lava Dome (Skamania County WA, #3). This being in my back yard, (and almost getting vaporized by the blast) I have paid pretty close attention the volcanic activity up there. After the initial dome building, there was a period of intrusion that build a rib upslope of the dome. I had thought that this must have filled in the saddle that defined the Lava Dome, but had never been in a position to get a picture at the correct angle to show it. This weekend finally got it. The saddle is entirely gone, and to my view, the dome now has essentially "0" prominence. My guess is that the maps have not been upgraded to show this 2005 - 2008 change. This time lapse video shows it pretty well also.
http://thewatchers.adorraeli.com/2013/02/02/time-series-of-dome-and-glacier-growth-at-mount-st-helens-2004-2012/