A diffusion/reaction model of SO2 uptake by snow containing liquid water is used to examine the snowpack processes controlling accumulation of dissolved S(IV) and S(VI). Surface deposition velocity vd (defined as overall accumulation rate divided by surface SO2 concentration) depends on the amount of liquid water in the snow, the time scale considered, the rate of S(IV) to S(VI) conversion in the aqueous phase, and the SO2 concentration. In the absence of any oxidation, vd for dense snow (specific gravity 0.4) with a moderate liquid water mass fraction (Xm=0.01) and SO2 concentration of 20 ppbv (parts per billion by volume) is calculated to be 0.026 cm s-1 after 6 hours. Deposition velocity increases by a factor of 3.2 for each tenfold increase in Xm and by a factor of 2.5--3.2 for each tenfold decrease in time. SO2 penetration into the snowpack is about 5 cm for the 6--hour case. In the presence of air containing 30 ppbv ozone and otherwise identical conditions, 80% of the accumulated sulfur is as S(VI), and the calculated vd is 0.036 cm s-1. A further tenfold increase in ozone concentration gives only a 70% increase in vd. A similar dependence is calculated for oxygen (catalyzed by Fe(III)) as oxidant, but that for hydrogen peroxide is much stronger and almost linear. A tenfold increase in SO2 concentration (with ozone at 30 ppb) results in a 2.3-fold decrease in vd. Wet snow with a liquid water mass fraction of about 0.1 gives a deposition velocity at 20 ppb SO2 of 0.12 cm s-1, with a penetration of only 2 cm. Calculated and observed uptakes of SO2 by snow are in good agreement. ¿American Geophysical Union 1987