Danger in the Mountains

Avalanche path on Mt. Huascarán, Peru. (photo by Servicio Aerofotografico Nacional de Peru)

Watch out for avalanches, landslides, and explosions!

Mountains can be dangerous places. It’s not just the cold and snow, the chance of getting lost, or falling off a cliff. There are bigger dangers. You definitely don’t want to get in the way of an exploding volcano, a hurtling avalanche, or a flash flood. Mountains command our respect!

Avalanches

Every year dozens of people are killed by avalanches. These sliding masses of snow and ice can let loose with little warning. They can reach speeds of more than 2 kilometers per minute and carry rocks, trees and people with them. Many avalanches are natural, but some are triggered by skiers, snowboarders, hikers and snowmobilers.

The people living near Mt. Huascarán in Peru have suffered some of the worst avalanches in the world. In 1970, a huge mass of falling rock and ice killed 18,000 people and destroyed the town of Yungay, Peru.


Landslides

Landslides can wash out roads and destroy homes and fields. In the pictures below, farmers cut down the forest that used to cover these steep mountains in Rwanda. They planted crops to feed their families. But, without the forest to catch and soak up rainfall, and without a strong network of roots to hold the soil in place, the soil washed away in huge landslides during a storm in 1988.

Before and after landslides in Ruhengeri, Rwanda (photos by Alton Byers)

Volcanoes

Steam eruption of Nevado del Ruiz (photo by NOAA)

Volcanoes are loud, spectacular, and deadly. In 1883, tremendous explosions from the volcano Krakatoa in Indonesia were heard in California. That is one-eighth of the way around the world!

One of the worst volcanic eruptions in history was at Nevado del Ruiz, Columbia, in 1985. The eruption triggered a deadly mudflow that sped down the slope, killing 23,000 people. The people in the town below did not have any idea that it was coming.

Aerial view of Mt. Pinatubo crater (photo by NOAA)

Scientists are getting better at predicting eruptions. In 1991, scientists spotted early warning signs of an eruption at Mt. Pinatubo, Philippines. Scientists sent out a warning to the people living near the volcano. The people were able to get away. They lost their homes and land but 200,000 lives were saved.

As the world's population grows, the land gets more crowded. More people are living in potentially dangerous mountain areas. What do you think can be done to help?

Would you like to see mountain hazards in action?

Try these links:

Anatomy of an avalanche
See an animated diagram of an avalanche (USA Today)

Volcanic Eruption
Flash animation (Savage Earth, WNET, PBS)

Popocatepetal volcanic eruption
Quicktime movie of of Popocatepetal eruption, Mexico (TV Azteca and CNN Interactive)

Fly over of Mount St. Helens
Mount St. Helens in Washington, USA erupted with such violence that the top of the mountain was blown off, spewing a cloud of ash and gases that rose to an altitude of 19 kilometers (NASA)

Zoom into Mt. Etna
Zoom into Mt. Etna, an active volcano in Sicily (NASA)

Find more great learning resources by searching our on-line guide. Or, click on the keyword to do an automatic search for mountain learning resources related to natural hazards.