1. The problem statement, all variables and given/known data When spring finally arrives in the mountains, the snow pack may be two meters deep, composed of 50 % ice and 50 % air. Direct sunlight provides about 1000 wats /m^2 to earth's surface, but the snow might reflect 90 % of this energy. Estimate how many weeks the snow pack should last, if direct solar radiation is the only source of energy. 2. Relevant equations Possible equations: Q=L/m, Q=C*delta(T) 3. The attempt at a solution L_water=333 J/g, L_boiling water=2260 J/g Not really sure how to start this problem. I know I am supposed to derived an equation for time, I would probably calculate the surface Area X Power/area to get the power. Then I would have to calculate the energy of the direct sun then I would divide the power by energy to ge the time.