Snow line is the lower edge of the permanent snow fields found on upper mountain slopes. The location of the snow line depends upon the height of the sun, latitude, winds, temperature, and moisture. The snow line on the same mountain range may change from year to year. In the tropics, the snow line is about 3 miles (4.8 kilometers) above sea level, and in the subtropics it is about 4 miles (6.4 kilometers) above sea level. The snow line of the Rocky Mountains of the United States is about 2 miles (3.2 kilometers) above sea level. In the Alps of Western Europe, it is about 11/4 miles (2 kilometers) above sea level. It is less than 1/2 mile (0.8 kilometer) above sea level in Greenland. It is at sea level in polar lands.
