11 Facts About Landslides

Mudslides, Landslides, Earthflows, Oh my

1. Landslides occur when masses of rock, earth, or debris move down a slope. Debris flows, also known as mudslides, are a common type of fast-moving landslide that tends to flow in channels.

2. Mudslides develop when water rapidly accumulates in the ground and results in a surge of water-saturated rock, earth, and debris. Mudslides usually start on steep slopes and can be activated by natural disasters.

3. Areas where wildfires or human modification of the land have destroyed vegetation on slopes are particularly vulnerable to landslides during and after heavy rains.

4. Landslides and mudflows can cause tons of damage, some of which can lead to actual injury including: Rapidly moving water and debris can lead to trauma; Broken electrical, water, gas, and sewage lines that can result in injury or illness.

5. Every year, landslides in the U.S. cause roughly $3.5 billion in damage and kill between 25 and 50 people.

6. Casualties in the U.S. are primarily caused by rock falls, rock slides, and quick-moving debris.

7. There have been many landslides throughout the years including the Rio de Janeiro landslide in 2011 which caused over 600 deaths.

8. It is not just on earth in which landslides occur. Throughout the solar system there has been evidence that landslides have occurred, on Mars and Venus specifically. Scientists have had trained satellites orbiting the planets to view the landslides

9. The May 1980 eruption of Mount St. Helens caused the largest landslide in history. A rockslide debris avalanche large enough to fill 250 million dump trucks to the brim traveled about 14 miles, destroying, amoung many things, nine highway bridges.

10. The debris avalanche from the eruption also formed several new lakes by damming the North Fork Toutle River and its tributaries.

11. On steep hillsides, debris flows begin as shallow landslides that liquefy and accelerate. A typical landslide travels at 10 miler per hour, but can exceed 35 miles per hour.