As of November 2006, this route had replaced the Jamapa Glacier as the standard route up the peak. Approach the glacier from the refugio by hiking up the obvious drainage. There is a well-traveled trail in the bottom half, but higher up the route-finding becomes very confusing, especially in the dark. There is an easy way, though there are tons of 4th & 5th class obstacles as well as legions of discarded wands that make it difficult to stay on the right path. In his guidebook for the area, Secor recommends scoping this part of the ascent in the daytime, perhaps on an acclimatization day. I strongly encourage the same. It's a beautiful hike and you'll save yourself lots of heartache. Of course, if you get off route, just continue up in the same direction until you hit snow. The route begins at a carin at the base of the glacier where the trail leading from the refugio deposits you onto the snow. Mark this location well in your brain, GPS, or whathaveyou. It will make life much easier on the descent. From this location, gain the ridge to climbers right that connects the "sarcofago" (a small, secondary peak to the north of Orizaba) with the main peak. Upon gaining the ridge, turn left (south) and start slogging up. It's about 3-4 hours from the beginning of the glacier to the summit. Getting lost is tough to do. Just go up. To descend, downclimb the route, taking great care to stay on the trail in the section immediately below the glacier. This is the most hazardous section apart from the glacier itself.
The climb is not particularly steep, though crampons and a general mountaineering axe are prudent. Ice tools are totally unnecessary. Some people report crevasses in late season, so a glacier setup (partner, prussiks, rope, anchor materials, wits) may be a good idea as well. When I was there, rockfall was not an issue (the route is not very steep) so a slip on hard snow or exposure in a storm are probably the most concerning objective hazards.
BETA PHOTO: This photo is taken from the Northwest. The yello...
BETA PHOTO: This is the view on the descent. The refugio is t...
The Jamapa Glacier from its base