11 Facts About Avalanches

Welcome to DoSomething.org, a global movement of millions of young people making positive change, online and off! The 11 facts you want are below, and the sources for the facts are at the very bottom of the page. After you learn something, Do Something! Find out how to take action here.

1. “Loose snow” avalanches account for only a small percentage of deaths and property damage. “Slab” avalanches (the most lethal) are cohesive plates of snow sliding as a unit.^["Avalanche Facts, Avalanche Information, Avalanche Videos, Avalanche Photos - National Geographic." National Geographic. http://environment.nationalgeographic.com/environment/natural-disasters/avalanche-profile/ (accessed August 1, 2014).]
2. Each year avalanches kill more than 150 people worldwide.^["Avalanche Facts, Avalanche Information, Avalanche Videos, Avalanche Photos - National Geographic." National Geographic. http://environment.nationalgeographic.com/environment/natural-disasters/avalanche-profile/ (accessed August 1, 2014).]
3. In 90% of avalanche accidents, the victim or someone in the victim’s party causes the snow slide.^["Avalanche Facts, Avalanche Information, Avalanche Videos, Avalanche Photos - National Geographic." National Geographic. http://environment.nationalgeographic.com/environment/natural-disasters/avalanche-profile/ (accessed August 1, 2014).]
4. The human body is 3 times denser than avalanche debris and will sink quickly. When the slide slows, clear air space to breathe, then punch your hand skyward. Once the avalanche stops, it settles like concrete.^["Avalanche Facts, Avalanche Information, Avalanche Videos, Avalanche Photos - National Geographic." National Geographic. http://environment.nationalgeographic.com/environment/natural-disasters/avalanche-profile/ (accessed August 1, 2014).]
5. Unlike its portrayal in movies, noise does not trigger avalanches. Avalanches are caused by four factors: a steep slope, snow cover, a weak layer in the snow cover, and a trigger.^["Avalanches." Avalanches. http://www.getprepared.gc.ca/cnt/hzd/vlchs-eng.aspx#a1 (accessed August 1, 2014).]
6. The vast majority of avalanches (90%) occur on slopes with angles between 30 and 45 degrees. Steeper slopes tend to continually slough snow, keeping a deep snowpack from building up. The snowpack on flatter slopes requires more force to move.^["10 Things You Didn't Know about Avalanches." 10 Things You Didn’t Know about Avalanches. http://www.climbing.com/climber/10-things-you-didnt-know-about-avalanches/ (accessed August 1, 2014).]
7. Avalanche risk is at its greatest 24 hours following a snowfall of 12 inches or more.^["Avalanche Facts, Avalanche Information, Avalanche Videos, Avalanche Photos - National Geographic." National Geographic. http://environment.nationalgeographic.com/environment/natural-disasters/avalanche-profile/ (accessed August 1, 2014).]
8. Avalanches can reach speeds of 80 mph within about 5 seconds.^["Avalanche Facts, Avalanche Information, Avalanche Videos, Avalanche Photos - National Geographic." National Geographic. http://environment.nationalgeographic.com/environment/natural-disasters/avalanche-profile/ (accessed August 1, 2014).]
9. The deadliest avalanche in American history was due to a train wreck in 1910. Roughly 96 people died in the incident.^["10 Things You Didn't Know about Avalanches." 10 Things You Didn’t Know about Avalanches. http://www.climbing.com/climber/10-things-you-didnt-know-about-avalanches/ (accessed August 1, 2014).]
10. If a victim can be rescued within 18 minutes, the survival rate is greater than 91%. The survival rate drops to 34% in burials between 19 and 35 minutes.^["Avalanche Facts, Avalanche Information, Avalanche Videos, Avalanche Photos - National Geographic." National Geographic. http://environment.nationalgeographic.com/environment/natural-disasters/avalanche-profile/ (accessed August 1, 2014).]
11. After one hour, only 1 in 3 victims buried in an avalanche is found alive. The most common causes of death are suffocation, wounds, and hypothermia.^["Avalanches." Avalanches. http://www.getprepared.gc.ca/cnt/hzd/vlchs-eng.aspx#a1 (accessed August 1, 2014).]