From the Seattle Post Intelligencer
A group of scientists planned to visit the mountain Monday and conduct a flyover to test for carbon dioxide and sulfur gases, which could suggest the involvement of magma. They'll also erect additional seismic sensors and sophisticated global positioning devices to measure activity.
http://seattlepi.nwsource.com/local/aplocal_story.asp?category=6420&slug=WA%20St%2E%20Helens%20Notice
Checking for that bulging...that would be a bad sign.