5.1.7 Grain types and stability of layered snowpack
Layers form in a snowpack from the various snowpack processes that we've discussed, including thermal gradients, melting/freezing, radiative processes, and precipitation events. Layers can represent weaknesses in the snowpack because fractures tend to occur along their interfaces.
Which of the following grain types commonly form persistent weak layers within a snowpack? Select the correct answers, then click Done.
The correct answers are a and d.
Depth hoar and other faceted grains have edged, flat surfaces. These grains inherently form weak layers that can reduce stability over long periods of time. The other types of grains, such as pristine snow crystals, do not last very long or form strong, well-bonded layers. Note that if a strong layer overlies a weak one, the situation can be unstable.