OverviewCerro Guanaco is a mountain in the Fuegian Andes in southern Tierra del Fuego. It sits on the end of a ridge that runs from Chile, across the international border into Argentina, and lies within the Lapataia Sector of the Tierra del Fuego National Park. The NP is readily accessible from Ushuaia, the principal city and hub in the immediate region. The Fuegian Andes lie to the east of Cordillera Darwin and mark the southerly extent of the whole Andean range. Heavy glaciation has produced a series of deep valleys between ridges that rarely rise more than 1500 m though remain capped by a relatively permanent snowfield with the occasional glacier. The tree line is around 600 m with shrubs and grasses extending above. The high density of peaks and views of the many lakes and Beagle Channel make this a worthwhile and enjoyable climb even for the well travelled. It can be done as a semi-rushed day trip or as part of a longer stay in the NP which is 630 sq km in area. Much of the NP however requires the company of an approved guide to visit and there are two biosphere reserves which are off limits. These kinds of restrictions enable the flourishing of a wide variety of birds and mammals to flourish.
Getting ThereGetting to Ushuaia: Ushuaia, though widely famed for being the southernmost city in the world is one of the harder places to get to in the region. This is partly because it is quite far from anywhere else and partly because it is on an island. There are a number of buses from Puerto Natales and Punta Arenas in Chile (they meet part way and transfer passengers), and also from Rio Grande, Rio Gallegos and El Calafate in Argentina. Numbers likely vary over the course of the year but one per day may be normal. Prices around on the order of US$15-40 with duration 9-14 hours. Don't recall ever finding a company office in Ushuaia for the companies that do this so on the way out best to do things by phone or via your hostel/hotel/a general agency. Make sure to book ahead. Ushuaia has a modern airport on its outskirts with frequent flights. There are a couple of agencies in town where you can buy tickets. Ferries are another option with various destinations. Travel from, to, or via the Falkland Islands / Las Malvinas may be problematic.
Getting to/around the NP: The easiest way to get to the NP, 11 km west of town is via one of the many scheduled shuttle services that run from downtown Ushuaia (the waterfront carpark at the corner of Maipu and Juana Fadul). A US$10 ticket covers a return trip, just say when you want to come back and from which stop on the route around the park, for there are several. There are several companies that do this, make sure to note their itinerary so you don't miss the times and places. Regular taxis can take you for perhaps US$15-20. As it's quite far, tricky to navigate and unimpressive till you're there, hiking along the roads isn't particularly recommended. Hitch-hiking not likely to meet with success as many vehicles will already be full. Can drive if you have your own vehicle I imagine, it's Ruta 3 you want. Stick to this road in the other direction and 5171 km later you'll end up La Quiaca at the Bolivian border.
RoutesThere's pretty much one route to the summit, with a little bit of flexibility nearer the top. It's around a 3 hour, 4.5 km distance, ~950 m climb. Several books I have say it's 8 km, whether that includes every twist and turn of the trail or is just plain wrong I'm not sure. Do it on Google Earth and it's around 4-5 km. The Google Earth altitude puts it at several 10s of metres less than reported in texts also but not sure what the spatial resolution is.
At any rate, from the Lago Roca camp site follow the edge of the lake round to the north-west for around 10 minutes till there's a fork and a sign on the right-hand side pointing to Cerro Guanaco. Follow the indicated path through the guindo and lenga forest ascending fairly easily and over a few streams. After perhaps an hour you will reach an opening where there are some great views back over the lake and surrounding mountains.
Continue on along the forest paths which changes into a muddy terrain in amongst some smaller tree species. There are a number of routes here so make sure to keep an eye out for paint marks, foot prints or litter to indicate the correct course and for how to get back. Break from the trees and follow the edge of a stream upwards and pass through yet more mud into the open at around 600 m altitude. In front you will see the Cordon de Guanaco running from left to right. Across the open grassy space in front and a little to the right you will see the beginning of a stony path that runs upwards and to the right towards the summit which is at the more or less the end of the Cordon. The grassy space is likely to be quite wet so pick your route carefully. There are some wooden post trail markers above so look out for these.
Although the ridge line is only a few hundred metres above you, the 'summit' is still 2 kms away to the right. While there is a temptation to hit the ridge-line early you may find it steeper than you expected, cause small avalanches of loose rock or come across difficult to avoid delicate plants so staying on the path is advised. The path may appear to end at the ridge crest but this is not yet the highpoint. Continue on with a little care, either staying on the apex or traversing round to the side for another 100-200 m for some huge views over the Beagle Channel and all the surrounding mountains. Though the very highest point is the edge of a sloping block and a little precarious to stand there are flat areas from which to admire the views and relax. Return via the same route.
ConsiderationsRed Tape: The mountain as mentioned is in the Tierra del Fuego National Park (Lapataia Sector) which has various regulations (e.g. camp only in approved areas, no pets, don't fish without permission, take rubbish with you etc.) and a several US$ entrance fee. The NP is right up against the generally unmarked international border with Chile so be careful to note where this is and avoid straying across it lest ye run into a patrol.
Weather: Unpredictable as with much of mountainous Patagonia, anticipate variable temperatures, wind, rain (1500 mm average per year), snow, and sunshine though conditions likely less severe than further west on Cordillera Darwin. Pretty far south so expect long days in the southern summer (Dec-Feb) and short days in the winter (June-August), with plenty more snow at all altitudes. See here for a useful summary of weather information over the course of the year.
Equipment: Can be quite boggy in places so gaiters and waterproof footwear can be useful any time of year, maybe crampons in winter. There are a few outdoor shops in the downtown area so you will be able to get various kinds of clothing, stove fuel and perhaps more technical items.
Camping/AccomodationCamping: Within the NP there are 6 camping areas, generally costing several US$: one near the trail head for Cerro Guanaco (Lago Roca) where there's also a restaurant, shop and showers, 3 others sitting close to each other 1-2 km to the south (Las Bandurrias, Laguna Verde, Cauquenes), and 2 others nearer the park entrance. The latter 5 are more basic. Stoves are permitted.
Places in town: Ushuaia is a very touristy area thanks to the range of outdoor and wildlife activities in the area, as well as trips to Antarctica. As a consequence there are many accommodation options in town but make sure to book.
Other things to doThere are a number of easy hikes in the NP, generally around lakes or to various lookouts though much lower than Cerro Guanaco. One of the includes a 10 km round trip from Lago Roca to the international border (Hito XXIV) through the forest and along the lakeside. This is a good way to explore some of the flora that grow on the forest floor like lichens, mosses, fungi and flowers as well as curiously shaped trees and time sculpted rocks.
Some water sports are also available such as kayaking. There are many other hikes, multi-day treks and climbs in the region, including on the Chilean side in the Cordillera Darwin, some north of Ushuaia (e.g. Sierra Valdivieso Circuit, Paso de la Oveja Trek, Laguna Esmeralda Trek) and also on Isla Navarino to the south (e.g. the Dientes Circuit). See the below links for some starters.
While in the area keep an eye out for creatures such as foxes, Magellanic Woodpeckers, condors, geese, beavers, and guanaco after which the peak was named. There are also many fish in the lakes. Beware any shellfish though as they may have been contaminated by toxins via marine algae.
Maps/books/linksMaps: You get a basic trail map from the park office which is sufficient for most purposes. Also see the Zagier & Urruty 1:50,000 Ushuaia Trekking Map which can be bought locally.
Books: Lonely Planet - Trekking in the Patagonian Andes (various authors/editions).
Local info sources:
Tourist Office: San Martin 674 / Website
National Park administration office: San Martin 1395 / Official NP website
Club Andino Ushuaia office: Fadul 50 / Website