| 14 Nov 2025
Behavior of Snow Containing an Ice Lens under Compressive Loading
Abstract. In order to understand the effects of strain rate on the mechanical response of snow containing an ice lens perpendicular to the loading direction, specimens with and without ice lenses were compressed at several different rates from 4 x 10-4 to 1.2 x 10-2 s-1. It was found that snow columns with an included ice lens follow the same behavior as homogeneous snow for the range of strain rates tested, the sole difference being a six-fold increase in stress at a given strain when an ice lens is present. For all samples, low strain rates (4 x 10-4 to 1.2 x 10-3 s-1) resulted in a smooth steady increase in stress with increasing strain, whereas at high strain rates (4 x 10-3 to 1.2 x 10-2 s-1) two loading regimes occurred; up to ~20 % strain stresses minimally increased, while higher strains led to a more rapid stress increase. Snow columns both with and without an ice lens showed the highest resistance to loading at intermediate rates (2.1 x 10-3 to 3 x 10-3 s-1) which allowed for reconfiguration of the ice particles whilst inducing pressure sintering to strengthen existing bonds. Stress differences between aged and fresh snow were distinct but not as large as those between ice lens-containing and homogenous snow, indicating that ice lenses have a higher contribution to snow strength than sintering alone.
To whom it may concern,
Blaisdell and Baker performed laboratory experiments of uniaxial compression on snow samples with an ice lens and without an ice lens. A range of piston velocities were implemented. While the experimental setup is novel, and a welcome contribution to the data-sparse field of snow mechanics, the presentation of the study and interpretation of results leave many unclear points and I recommend major revisions prior to publication.
One major issue is the use of stress-strain curves, yet what was measured was piston displacement and piston resistance force. As the authors state in lines 320-338, the compaction is not occurring uniformly throughout the sample, and the samples with an ice lens are heterogeneous themselves. This contradicts the presentation of stress-strain curves which are not for specific locations within each sample (as far as I can tell) but for the samples in their entirety. Thus, concepts such as strain rate, stress, and strain should only be applied to specific locations or regions within the sample, not for the sample in its entirety. As presented, the reader is lead to believe that the strain in the 2 mm ice lens is the exact same as the snow directly below the piston which is certainly not the case.
Another major issue is the use of the word “strength” throughout the manuscript without any working definition. I refer the authors to texts such as “Strength of Materials” by Timoshenko (1976) where an overview of strength theories is presented. In short, the purpose of strength theories is to predict when failure will occur. Yet it is unclear in the manuscript how failure is defined or if large rise in piston resistance force is from the snow compacting against the ice lens/lower boundary.
The third major issue is lack of clarity on the samples sizes and tests performed. The authors mention a variety of tests that were performed with varying piston velocity, presence of an ice lens, aged and new snow, and selective MicroCT imaging; yet these are not accompanied by actual sample sizes for each test configuration. I suggest a table that clearly states all the trials performed with accompanying sample sizes for each variation.
In addition to these three major issues, a variety of minor points are made below.
Introduction:
Lines 19-20: Strange phrasing, is there a citation for this discussion of “horizon in the snowpack with low shear resistance.”? Do you have a source for “ice lens due to its thinness compared to the overall snowpack”? Also, it is not intuitive that an ice layer would be considered a “weak horizon”, wouldn’t the surrounding snow be weaker by comparison?
Line 23-24: The statement is quite obvious and the Hammonds et al. citation seems misplaced.
Line 30: Is there a reference for “a snowpack’s strength can vary widely over timespans as short as 12 h”?
Line 43: The acronym DIC has not been defined.
Line 48: The acronym DVC has not been defined.
Methods:
What is the uncertainty/tolerance range for the 2 mm ice lens?
Figure 1 calls into question the perpendicularity of the ice lens.
Lines 122-123: “No detectable difference” by what metric? It is not obvious that day-old snow after sifting would have the exact same amount of sintering both to the ice lens and within the snow itself as minute-old snow. Furthermore, this contradicts the statement on line 30.
Line 129: The acronym MTS has not been defined.
Lines 135-136: If no visual difference was detectable, what about with the post-processing analysis software?
Line 141: What was the mass of the plunger?
Line 155: What was the chosen sample rate?
Line 160: Which data acquisition system was used?
Line 175: Future work should be stated in discussion, not methods.
Lines 181-193: Consider moving this content to an introduction/background section
Lines 194-200: Consider moving this content to discussion.
Results & Discussion:
Line 201: Consider separating results and discussion as is more typical in scientific papers.
Line 203: Consider moving this section to an introduction/background
Figure 2: Why is the solid line in this figure different from the red line in Figure 3b?
Figures 3, 6, 7, and 8 are difficult to read and interpret with many overlapping lines. Also, the legends are not always representative of the plots with more or less lines than the legend contains.
Line 266 and line 280 are contradictory
Line 276: It is unclear in the results how you reach this conclusion.
Figure 10: What is the line on these plots?
Lines 315-319: Perhaps the starkest difference between your lab tests and a field setting is that the ice lens can translate vertically within the sample container.
Figure 7b: Why are there large decreases in “stress” at 35-40% “strain”?
Conclusion:
Line 399: Well stated that “resistance to loading” was measured, but the conclusions should be rewritten and revisited based on the major issues detailed earlier.
Works cited:
Timoshenko, S. P. (1976). Strength of Materials: Part 2 Advanced Theory and Problems (3rd ed.). Robert E. Krieger Publishing Company, Inc.