Cerro Cornu

Frosty camp

According to Summitpost, Cerro Cornu is the highest peak in Argentine Tierra del Fuego, though other sources suggest that Cerro Tonelli north of Ushuaia may be slightly higher. This is not saying much, since the much higher and more glaciated Darwin Range is entirely in Chile. However, Cornu appealed to me because it is along the way to Ushuaia, is fairly close to a road (Ruta Nacional 24 J), and has no information about it online. It would be a sort of adventure, and I had seen too little of that on my too-touristic trip.

Sunrise above camp

I had camped on an abandoned spur road near a gravel pit, and now it was time to figure out the peak. I had initially thought I would just hike and scramble up the southeast ridge, but the horn giving the peak its name looked too sharp on closer inspection to make that likely. The broad southwest face looked like another option, but reaching its base would require a lot of distance below treeline, and I suspected that getting above the vegetation might be the crux. I did not have a clear idea of what would work, but the peak did not look sheer enough to prevent me from reaching the summit one way or another.

Lasifahaj swamp

The first order of business was crossing the Rio Lasifahaj to reach what I hoped would be a useful old logging road on the other side. From my tent, I picked up some wild horse trails leading down into the river’s flood plain and through the scrub beech forest to some sort of open swamp. This late in the season, the swamp was spongy but partly dry, and I was able to wind my way over to the riverbank, sometimes sinking to my ankles in the ground moss. The river looked discouraging where I reached it, deep with fallen trees clearly visible on the bottom, and it was cold outside, with frost on the ground. I almost turned around, but headed downstream and eventually found a place where it split into three channels, and the bottom was gravel. I took off my pants and socks, took the insoles out of my shoes, then put them back on to try to ford. This has the big disadvantage versus going barefoot of soaking the shoes, but when crossing cold water I prefer to move faster, have better footing, and not risk being stabbed in the foot. The first two channels were not bad, but the third was briefly thigh-deep. I scrambled up the bank on the other side, sat on a log, and squeezed as much water out of my shoes as I could before getting dressed and heading back into the forest.

Start of the thrash

The Patagonian beech forest here is moderately annoying, with some impenetrable thickets and mostly woody plants, along with Patagonian super-burrs in some open areas. This made it slow going uphill away from the river, but fortunately the old road was still mostly clear, if far from rideable. I followed a game trail along the road until meeting a side-stream just before Cornu, which I crossed on some logs, then left the road where it fades in a clearing with a bunch of beaver dams. I was only a few hundred feet above sea level, and treeline was somewhere between 1500 and 2000 feet, so I had a fair bit of bushwhacking to do. The bottom part was the worst, with dense undergrowth and plenty of deadfall, but things improved as the slope steepened. The game trails disappeared, but the beeches were open enough that I could wind my way up following ridgetops and seasonal watercourses.

Bowl with notch on right

I finally emerged in a talus-field, and happily hopped my way up toward the southeast shoulder. I had not yet decided whether I would try the southeast ridge or southwest face first, but knew that I had to traverse below the horn, so I made a rising traverse northwest across dinner-plate talus and slabs toward the bowl between them. Reaching the edge of the bowl, I discovered that it was sheer on both sides to well below my current position, so I would have to lose elevation to get onto the southwest face. The sun had started generating mist on the east sides of the peaks, so I could not see the upper mountain, but it looked like I could reach the saddle between the peak and its horn. There was a vertical-looking step above that, but hopefully I could find a weakness or work my way around the other side.

Lower gully/ramp

I descended a convenient little ramp on my side of the bowl, with a final chockstone requiring a few moves, then made my way across old moraines toward the notch, where a final bit of easy third class got me to the ridge. I tried attacking the step directly, climbing some slabs and ledges, but a final dihedral/crack felt too hard for me, especially with ice and bits of fresh snow. I backed off, then contoured around right, hoping to find something leading back to the ridge higher up. I found a loose gully perhaps 100 yards along the side, and while I could not see too far in the mist, I started up. It was not a “gimme,” with some class 3-4 sections here and there, but I found a reasonable way up the gully and the ramp to its right, eventually rejoining the southeast ridge well above the step.

Horn from upper ridge/face

I continued upward in the clouds, picking my way up loose rock and occasional solid slabs on the left, while the right side became a sheer cliff. There were no particular difficulties on this part, and with a final short scramble I reached the broad summit plateau. The mist made it hard to see whether I had reached the highest point, but it seemed so, and I found a small metal cross, so I figured I was on the summit. I straightened the cross, then put on all my clothes and sat down out of the wind to enjoy some Mantecol and hope for a view. I had a few gaps in the clouds before I packed up, then it began to clear as I headed down, allowing me to clearly see the Cornu Glacier, the horn, and some lakes to the east. Had the forecast not called for rain that afternoon, I would have hung out longer.

I retraced my route on the return, thankful that I had been recording a track in the woods. The weather began deteriorating on the traverse around the horn, but while there were more serious-looking squalls to the west, I only suffered a few snowflakes. I stopped for water at a rivulet I had found on the way up, safely above beaver territory, then thrashed my way down to the old road. With warmer temperatures and a bit of success in me, the return thrash and river ford felt easier. I returned to my tent by mid-afternoon, and could probably have ridden on to Ushuaia, but I had enough food, was enjoying my solitude, and did not relish riding in the rain. I made myself a thermos of hot tea, then lay down on my pad to read a novel on my phone and listen to the intermittent rain.

2 responses to “Cerro Cornu

  1. Mike Gilliland says:

    Hi Sean,
    I’ve enjoyed traveling with you this winter as you head ‘toward’ the south pole. I’m more than willing to read the rest of the ‘book’ to see how it ends, but I’m curious to see if you are going to depart South America close to where you currently are, or if you are going to peddle back to Santiago?
    Be safe,

    1. drdirtbag says:

      I’m actually back in the States now, but behind on my writing. I flew out of Ushuaia, the southernmost town on the Argentine side. While some people do ride north, it’s often against the prevailing winds, making it a brutal slog. Those two easy 90-mile days I did would have been four hard 45-mile days in the other direction (5 MPH for 9 hours).

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