Supplementary material to "Comprehensive Assessment of Stress Calculations for Crevasse Depths and Testing with Crevasse Penetration as Damage"

S1: Firn density considerationsWe did not take firn density into consideration in the surface crevasse depth calculations.Because the surface topography included with BedMachine is corrected for firn density, the amount of ice in terms of integrated density that the crevasse extends through will be the same.(This is true because we used the Nye crevasse theory.The geometry driven changes in stress intensity factor included in LEFM would mean that the integrated density of ice above the crevasse tip would change.)This will give a lower fraction of penetration for the surface crevasse.However, the lower rigidity of firn would tend to reduce this effect by making the extra penetrated length a lower fraction of the total rigidity of the ice column.Lai et al. (2020) show this in their supplement.More importantly, however, basal crevasses make up most of the total crevasse penetration (see Table 4 in the main text).