Andes Expedition

When you climb out of the tent this morning, there is a blanket of snow on everything. How beautiful! The sun is shining and although the air is cold, you know that by noon most of it will have melted and the mountain people will shed their heavier clothing and seek refuge from the sun.

While you knew Huascarán would be covered in glaciers, you have to admit you're a bit surprised to see new snow. It is the dry season, after all. During these months, from May to September, the weather is much more favorable for expeditions. If you were to come during the rainy season, from October to April, Huascarán would almost always be covered in clouds, and thunderstorms and rain would seriously complicate your climb. This is what high-altitude mountains do-they act as a weather barrier, extracting large amounts of water from the atmosphere. This is one of the ways that mountains are able to supply the streams, rivers, and lakes that people depend on for water.

A mountain stream. Photo: Florencia Zapata

Thinking back to a river you crossed earlier in the expedition, you recall that 80 percent of the water that humans use comes from mountain ranges like the Andes. Without mountains, people all over the world would not be able to drink, clean themselves, generate electricity, or water their crops. Back at the river you marveled at the different ways mountain people got across. Now, because it is the dry season, they are able to swim the pack animals to the other side. On some of the narrow stretches, you saw rope bridges and baskets hanging from pulleys. During the rainy season when the rivers are full and flowing rapidly, the people of the Andes blow up dried animal skins like balloons and float them across the river, loaded down with supplies.

Where does this water go when it leaves the Andes? Ask the team Geographer to pull out the world map. Once you've located the Andes, try to determine where the water that falls on either side of Huascarán ends up ultimately.