6.1.9 Hardness, 2

The more formal way of determining hardness is to use a ram penetrometer, which measures resistance as it is thrust into the snowpack layer. The greater the resistance, the greater the layer’s degree of hardness.

Illustration of a ram penetrometer, a formal test for measuring the hardness of a layer of snowpack

Here’s a hardness profile obtained with a ram penetrometer.

Sample hardness profile measured by the ram penetrometer

What do you think the thin layer near the top of the snowpack consists of? Select the correct answer(s), then click Done.

The correct answers are b and c.

Penetrometer resistance is very high for the thin layer, indicating that the grains are tightly bonded and likely to be crust. It could also be a buried dirt layer, since these often form hard ice layers. It cannot be depth hoar or low-density grains; these have a low degree of bonding, which makes them easy to penetrate.