A typical pack of freshly fallen snow has a density of 100 kg m^-3 and consists of ice crystals which can be modelled as spheres of radius 0.5 mm. Show that if the snow pack is sufficiently deep it would be expected to have a visible-band albedo close to 1, and estimate the depth necessary for this to occur. The absorption coefficient for light in ice can be taken as 0.01 m^-1, and the density of pure ice is 920 kg m^-3.