Final answer:
The temperature of the snow at the bottom of a snowpack typically stays at or near 0°C, taking time to absorb heat, with sublimation occurring at higher altitudes and lower pressures.
Step-by-step explanation:
The snow at the bottom of a snowpack typically remains near the freezing point of water (0°C). This is because enormous heat is required for phase changes, and snow, being in the solid phase of water, requires time to absorb heat from the surrounding environment, even when the air temperature is above freezing. Additionally, snow has a high specific heat, meaning it can absorb a lot of heat before it begins to melt. Water also loses heat more slowly than land does, which affects the temperature of snow-covered ground.
In regions of high altitude, such as above 15,000 feet, permanent snow and ice are present due to the lower atmospheric pressure and temperature. At these pressures and temperatures, the phase change from solid directly to gas, known as sublimation, becomes more common, contributing to snow loss without melting.