Not sure what kind of information your son needs, but here's a little. My husband and I visited the volcano in 2008. It's a barren mountain, still active, with smoke coming out of vents on the way up. No vegetation has yet started to take hold. It took about an hour to climb, and the wind on the ridge was really strong. We couldn't stay long at the top for fear of being blown over, so we did our descent shortly after we arrived. The descent was awesome -- it took only about 3 minutes to get down because we ran down the steep slope, which was covered with tiny, light-weight volcanic pebbles that made the experience something like running down a sand dune. A couple of other people had a board or box and were surfing down the side. Amazing!

My pictures are available at http://aprillilacsphotos.shutterfly.com/1312. Cerro Negro is in pictures 57-63. If you need further information, let me know. My husband is a geologist and could add a few remarks if that would be helpful.