You tube

Here are some you tube clips of large avalanches that have been set off, gives an idea of scale. Also in one someone is skiing on the avalanche, does anyone know if this is a thing only been able to find a few examples.

http://www.youtube.com/watch?v=99j17GL3qlE

http://www.youtube.com/watch?v=B0RWLxOFGLY

http://www.youtube.com/watch?v=3HxxzfUfFGk