A hardness difference between the weak layer and the surrounding layer is considered significant if it is greater than how many steps?

• A. 0 steps
• B. 2 steps
• C. 1 step
• D. 3 steps

Answer: (B)

In snow stability analysis, the contrast in hardness between a weak layer and its surrounding snow tells you how well the weak layer is bonded to the layers above and below. We assess hardness on a simple step scale, and a difference of more than two steps between the weak layer and the surrounding layer is considered significant. That means if the weak layer is at least three steps softer (or harder, depending on context) than its surroundings, the boundary is a strong indicator of potential failure under load. A difference of one or two steps is not seen as reliably indicating a weak plane, whereas a difference of three steps or more points to a pronounced contrast that can localize shear and promote avalanche release. So, the threshold used is two steps in the sense that the significant change is “greater than two steps.”