Fig. 10.

Normalized steady-state crack speed as a function of weak layer elastic modulus and weak layer strength, with a slab elastic modulus $E_{\text{slab}}$ = 15 MPa (same plot as in Fig. 4 where $E_{\text{slab}}$ = 5.2 MPa). The colored dots (white outlines) represent individual simulations, the colored background corresponds to the semi-empirical model (Eq. 2). The yellow background indicates snowpack conditions where crack propagation cannot occur (up triangle for the simulations). The red background shows snowpack conditions where the weak layer spontaneously fails without any initial crack (down triangle for the simulations). The colormap is graduated with normalized the crack propagation speed by the slab shear wave speed ($c_{\mathit{wl}}/c_s^{\mathit{slab}}$)