A range of information from various sources: avalanche accidents and incidents from the worldwide, national, and local perspectives.
Avalanche.org
Current season accidents, as well as accident reports for previous seasons: U.S., Canada, and World.
http://www.avalanche.org/accidents.php
Canadian Avalanche Center
A general analysis of trends and factors causing avalanches, based on investigations into reports of serious avalanche incidents.
http://www.avalanche.ca/cac/library/incident-report-database/view
Cyber-Space Avalanche Center
Worldwide accident reports from the current season back to 1996; searchable and sortable database.
http://www.avalanche-center.org/Incidents/
Colorado Avalanche Information Center (CAIC)
A detailed database of U.S. and World avalanche accident statistics. Statistics and graphs are very comprehensive and separate accidents by year, state, and user groups; also provides written accident reports.
Colorado statistics: accident reports for fatal avalanches, notable incidents, or interesting accounts from 1997 to present. http://avalanche.state.co.us/accidents/colorado/
U.S. statistics: http://avalanche.state.co.us/accidents/us/
Overall statistics: http://avalanche.state.co.us/accidents/statistics-and-reporting/
Gallatin National Forest Avalanche Center (Montana)
Local Montana avalanche accident reports, along with a link to Colorado (CAIC) for U.S. and World reports.
https://www.mtavalanche.com/
Glacier Country Avalanche Center (Montana)
Regional Montana incidents and near misses; 2004-2005 to present.
Northwest Weather and Avalanche Center (Washington and Oregon)
Accident summaries from 2000-2001 to present.
http://www.nwac.us/accidents/
Also graphs of the following U.S. and Northwest Accident Statistics:
http://www.nwac.us/accidents/statistics/
Utah Avalanche Center
An extensive collection of statistics and graphs.
https://utahavalanchecenter.org/detailed-information
Bridger-Teton National Forest Avalanche Center (Wyoming)
Summaries and information related to Wyoming avalanche fatalities, from 1913 to present.
http://www.jhavalanche.org/fatalities.html