| Remotely triggered avalanches and whumpfs are commonly observed in many mountain ranges, but have received little research attention in the past. These events are generally associated with persistent weak snowpack layers.;Remotely triggered avalanches and whumpfs are contrasted to avalanches that were not remotely triggered. Significant differences were found in snowpack properties of both the weak layer and the overlying slab. Additional experimental data collected at the sites of whumpfs indicate that fracture of the weak layer is coupled to bending of the overlying slab. An experimental technique was developed to measure the propagation speed of this coupled system. The measured speed was 19.9 m/s, substantially slower than estimated values. A theory is presented that explains this propagation phenomenon. Critical to this theory is the collapse of a weak layer when fractured, and bending of the overlying slab. Experimental data are presented to support this theory. |
