In regions where the temperature always remains below freezing point, precipitation occurs in the form of snowfall.
Wherever the rate of snow melting or its evaporation is lower than the rate of snowfall in a year, snow accumulates into great mass of ice.
Permanently snow covered regions of this type are called snow- fields.
Snow-fields occur in polar regions and on high mountainous areas.
Snowfields are always found above the snow line. Snow line is an imaginary line above which there is permanent snow. The height of the snow – line is not uniform
and is affected by latitude, amount of snowfall, direction of winds and slope.
Region permanently covered by snow and ice is called snow-field.
Bibliography : NIOS Geography Book