For those not following this, seismic activity increased dramatically the last 24 hours -- the instruments on the mountain are virtually saturated, and you are starting to see the Mt St. Helens events on the meters on Rainier and Hood. They've now escalated from the lowest alert level to the middle of three. Definitely the most intense earthquake activity since the last dome-building episode in 1986.

That being said, what's happening isn't exactly huge. The level of seismicity is much lower than before the 1980 eruption sequence started (in the week of activity that March before the first eruption, there were dozens of quakes of > M 4.0), and while they have closed the mountain above the timberline, they haven't closed the visitors center or trails further downslope. If it keeps accelerating for another week, though....