The avalanche is one of nature's most poorly understood killers. Review the facts about these massive slides so that you can understand them better.

At least 90,000 avalanches occur every winter in the U.S. -- most between November and March.

Most avalanche accidents -- 99.9 percent -- occur in the backcountry which is outside of ski areas with avalanche control.

Asphyxiation, or breathing carbon dioxide, is the cause of 75 percent of avalanche deaths. The remainder of deaths are from trauma caused by hitting trees and rocks on the way down. Only 2 percent of victims live long enough to die from hypothermia.

Avalanches pick up speed as fast as a race car -- they can go from 0 to 80 mph within about 5 seconds after the fracture occurs.

Avalanches are the only natural disaster in which human casualties are most often caused by the victims themselves.

Contrary to popular belief, spitting to determine which way is up will not help you if caught in an avalanche because once the snow stops moving, avalanche debris becomes like concrete -- you can't dig yourself out.

The odds of surviving burial by avalanche are less than 50%.

In North America and Europe, avalanches kill 150 people per year on average.

People ages 21-30 are the most likely demographic to die in an avalanche.

Snowmobiles are more likely to be caught in avalanches than hikers, skiers, or snowboarders.

Read More Avalanche Facts >>

Then, tune-in tonight at 9P et/pt to "Buried Alive" to find out how avalanches accelerate, what g-forces they create, and how they bury their victims.