This route is a complete traverse of the most substantial portion of the crater rim (from Companarios to Pico Noreste). It is quite lengthy and requires the ability to move quickly and confidently over moderate alpine terrain up to class 4. The traverse can be completed in either direction, although it is probably best to start from the south (Companarios) in order to tackle the most difficult sections early.
From the state-run hut at 4,050 m, take the wide path which ascends from the opposite side of the road and leads to the saddle between Pico Humboldt and Pico Noreste (see topo map on main page). From this saddle, the trail which leads over the summit of Pico Noreste can be seen clearly to the right. If you choose to complete the traverse from north to south, follow this trail now. Otherwise, keep in mind that you will exit the traverse via this trail.
Descend directly to the floor of the crater, passing Ombligo on your right and the lake of the moon on your left to intersect the gravel road (which is now inside the crater). Ascend the slope directly ahead via the obvious trail (clearly visible from the crater floor) to gain the ridge below the peak Lower Companario. The difficult climbing begins from this point.
Upon reaching the ridge below Lower Companario, turn right and climb along the ridge, passing to the left of the peak to regain the ridge on the other side. It is possible to go over the peak directly, but it is better to save strength for the major summits (Fraile and Aguila). According to xpmexico.com, the route which circumvents the peak is marked with cairns. I failed to find any of these cairns and simply followed the "path of least resistance."
The route then proceeds, more or less on the ridge to the summit of Higher Companario (marked by a cross). I found this to be the most difficult section of the entire traverse with a tricky step where some potentially class 5 moves were required. We may have been slightly off route however. Continue on the ridge past an evacuation route (which drops to the Lake of the Sun) to reach the base of the pyramid representing Pico de Fraile. Here, approximately 55 m of class 4 climbing must be negotiated, including an interesting near vertical section with a wide hand crack. Further on, move around to the right for the easiest line to the summit.
The descent down the north side of Pico de Fraile is considerably easier (Class 2) and is the route of ascent for those coming from outside the crater. Continue on the ridge over Pico Burkart and Pico Ordonez. It is possible to circumvent Pico Ordonez and save some time by passing to its right (on the inside of the crater). It is necessary to move quicky here, however, due to significant rock fall potential. We encountered some snow thorugh this section.
Climb back onto the ridge when it becomes convenient and proceed towards the summit of Pico Peschel. Apparently, it is possible to pass to the left of the peak, although we climbed more or less directly over the summit. From this point, Pico de Aguila is visible and the preferred route of ascent can be seen as a prominent gully with a sandy trail leading directly up it. Descend to the sandy notch where another escape route leads down to the crater. The ascent gully for Pico de Aguila begins slightly below and to the left. Climb the obvious path upwards which leads to more class 4 terrain. Move left to bypass some steep sections and continue upwards until the cross marking the summit comes into view. From here, its an easy scramble to Toluca's second highest peak.
From this point, it is probably best to follow the ridge down towards Pico Noreste, keeping to the right and as high on the ridge as seems reasonable. We followed an obvious path which descended quickly and found ourselves traversing on steep snow on the outside of the crater. This route was exposed to rock fall and self-arrest would have been difficult in the event of a slip. We also had to down-climb a tricky class 4 gully (glazed with ice) to reach the ridge and the trail to Pico Noreste. If I were to do the climb again, I would search for a better exit route from Aguila.
After descending from Pico de Aguila, it's an easy hike over Pico Noreste and back to approach trail. The road and hut can be seen below and to the left and are reached in about 30 min.
1) Helmet -- A helmet is absolutely critical for this climb due to the possibilty of rock fall.
2) Rope -- A rope may also be carried to assist in the more exposed sections and is probably necessary for those without reasonable experience on alpine rock routes. In other words, if you think there's a chance you might need the rope, then take it.
3) Crampons -- It is unlikely that crampons will be needed, but obviously conditions vary and ice may be present. Crampons would also be helpful should an escape via one of the evacuation ramps be required.
4) Rock Pro -- We carried a set of Stoppers and BD Camalots #0.5, #0.75, and #1. We never roped up and thus never used the gear but some parties may find comfort in using it. If you're confident on UIAA II rock, then you don't need rope or pro.
5) Ice Axe -- I took mine, but only used it on the exit from Pico de Aguila.
Experience and Preparation
Experience in moving quickly on moderate alpine terrain is absolutely critical for this route. We took 6 hours hut to hut, but inexperienced parties using a rope could easily take more than 8 hours. Additionally, the entire route lies above 14,000 ft, so good acclimatization is essential. Climbing La Malinche first or spending a day hiking around the lakes is not a bad idea.
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