Question

Why does not all the snow on the mountains melt to water after winter is over?

Answer 1

Snow and ice reflects and absorbs the sun’s energy in a different way, while snow would almost reflect all the light incident on it, ice tends to only reflect about 67% of the sun’s energy. In addition to this, the mountains where there is snow present, they are generally towards the poles where there is lesser sunlight.

Complete answer:
When the snow is newly formed, then it reflects about 90 percent of the sunlight which is incident upon it. This implies that the sun’s energy is not powerful enough to melt clean snow. And when the snow melts, it is not because of the sunlight. Snow does not melt on a spring day because of the sun’s heat as it is too low. It melts because of the warm breeze of the sea.

After snow is turned into ice, a different problem arises. Clean ice absorbs about two-thirds of the sunlight that is incident upon it - but ice is transparent enough for the light to penetrate quite a long way which is about 10 meters or more before the absorption takes place.Snow on the mountains does not melt altogether at once because every kilogram of snow requires around 33600 Joules of heat energy in order to form water at $0^{\circ}C$.

Note: Every year, with the beginning of the warmer summertime, the snow in the mountains starts to melt. Sudden melting of large amounts of snow can even cause flooding in some regions and often happens around the globe. The advent of climate change and global warming causes this effect to happen more frequently.