©2006, 1997 WGBH Educational Foundation. All rights reserved.

Adapted from NOVA: "Avalanche!". A NOVA Production by the WGBH/Boston Science Unit in association with La Cinquieme and Sveriges Television. Stock footage courtesy of Icelandic National Television Service, 365 Media/Channel 2 Iceland, and Stephen Kroschel. Animation courtesy of David Woolard and Paul McGeoch, Pictures on the Wall.