Glen's flow law (${\dot{ϵ}}_{ij}=\mathcal{A}{\tau }_e^{n-1}{\tau }_{ij}$)

A constitutive law for ice creep relates deviatoric stress ${\tau }_{ij}$ and strain rate ${\dot{ϵ}}_{ij}$ through an effective stress ${\tau }_e$ and a temperature-dependent rate factor $\mathcal{A}$. The commonly used exponent is near three. Homogeneity of degree $n$ explains the combination $u/N^n$ in pressure-dependent basal sliding laws when geometry and rate-factor scales are fixed.