The Ruta Normal ascends the Volcan Osorno on its southwest aspect, mostly up a broad shoulder on the summit glacier. It is the most commonly climbed route on the mountain. In good conditions, it's an easy snow climb, but it may have seasonal ice. Glacier travel technique is required; crevasses and small seracs are present, especially on the upper part of the route. Summer weather is mild but variable and visibility can be quite bad if it's cloudy.
This route has a reputation as something of a trade route...and it's true that it is a popular guided day-climb. But, it is still a long climb over terrain with glacial hazards, and at least 20 fatalities have been recorded on the mountain. Keep an eye on the weather forecast, and review your crevasse-rescue technique.
Permission from the Chilean forest service (CONAF) is required, although it is not difficult to obtain; inquire in the CONAF hut at the trailhead. As of January 2010, no fees were assessed for this route. Guide services are available on the mountain, but properly-equipped, competent climbers can do this route independently with no trouble.
Begin by walking up an old jeep trail which begins behind the CONAF hut. This road is constructed in loose black pumice and is a bit of a slog. You will encounter snowfields after about 200-400m of climbing, seasonally dependent; the going is easier on the snow.
Continue up the mountain to the top of the highest ski lift. From here, continue northeast either on the ridgeline or next to the ridge in snow. After about 350m (about 2000m altitude) you will encounter the lower edge of the summit glacier. Most parties elect to rope up here.
Head up the glacier, staying on the apex of the ridge, heading east and northeast toward the summit on 30-35 degree snow. In January 2010, the snow here was very consistent and uniform. At about 2400m, you will encounter an area of seracs, proto-seracs, meringue, and mounds of fallen debris. One option is to move through the seracs to the right, which is easier climbing but exposed to the largest seracs and some deep crevasses. To the left the seracs are smaller and less evil-looking, but the snow there is steeper (up to 45 degrees). Once through the seracs, reach the summit by crossing a couple hundred meters of flat snow. The view of all of northern Patagonia will absolutely knock your socks off!
The trailhead is located near the Refugio Teski, see description on the Volcan Osorno page. Descend the same way you came up.
Pickets (3 or 4) are useful. A few ice screws may be necessary in colder weather. Don't bother with rock pro. A GPS is also useful if it's cloudy.
Climbers on Volcan Osorno are subject to extremely strong UV exposure. Bring goggles or glacier glasses, and the strongest sunblock you can find.
BETA PHOTO: Volcan Osorno from the ski area parking lot, Janua...
Seracs and debris guarding the summit of Volcan Os...
Southwest Ridge approaching the glacier traverse.