Layer and crust development in a Central Sierra Nevada snowpack: some preliminary observations

Snow surface crusts and subsurface 'ice' layers densify exponentially. Crust thicknesses range form 4 to 10 cm; layer thicknesses are greater, ranging from 6 to 28 cm. Crusts exist on the majority of non-snowfall days and individually persist from 2 to 20 days. Layers may persist up to 50 days. All layers formed from burial of surface crusts under new snowfall. Pit studies show that layers can be discontinuous and that it is inappropriate to extrapolate point estimates of internal layer properties to wider areas.