A few of us were among the first to obtain permits to climb MSH after the volcano was reopened to the public after the big boom.
It was an incredible experience. The hike thru the lower elevations was thru devasted forest and the fresh lava rocks, not having been exposed to weathering for long, was razor sharp. The last 1,000' was up a steep slope, covered with deep, powdery ash. 1' forward and 4" back.
The top was a narrow crater rim that ran about 270 degrees around the blown-out area. Inside, there already was a 750' lava dome, eerily smoking down in the crater. What sounded like constant rainfall on this sunny day was rockfall into the crater, with rocks from the size of marbles to those the size of vehicles, constantly falling into the caldera.
Once we get thru this next period of activity, I'd urge folks to get a permit to climb MSH and have this experience for themselves.