The extended column test is a snowpack test that is similar to the compression test but uses a much wider column of snow that gives an observer a better indication of fracture propagation. It involves applying an incremental load to the column and then monitoring it to see the point at which it fractures, and how far the fracture spreads along the weak layer. 

An avalanche technician performing an extended column test.

Avalanche Canada forecaster James Floyer conducts an extended column test.

This video follows an Avalanche Canada field investigation into snow and avalanche conditions near Barkerville, BC on 26-Jan-2017. The failure layer in the extended column snowpack test was the January 17th surface hoar layer, which comprised of 5mm surface hoar crystals.

Glossary

Extended Column Test