![](/sites/default/files/2019-02/lionhead_pit.png)
Snowmobilers in the Lionhead area got unstable test results, easily propagating fractures in ECT tests on a weak layer buried about 50 cm deep. Photo: J. Norlander
Snowmobilers in the Lionhead area got unstable test results, easily propagating fractures in ECT tests on a weak layer buried about 50 cm deep. Photo: J. Norlander