Despite the fact that the snow masses in the snow-bearing mountains provide vital water resources for ecosystems and society, but they are sensitive to climate warming. With the occurrence of climate change in recent years, the amount of snow storage in the snow-bearing areas has decreased significantly. Snow plays an essential role in providing the world's water resources, climate and biogeochemical processes on the earth's surface. he global importance of snowfall is undeniable. Snowfall causes the earth's surface to cool. On the other hand, water from melting snow supplies the amount of fresh water needed by one sixth of the world's population. Snow also attracts tourists and strengthens the tourism industry. Recreational activities, including the skiing industry, attract billions of dollars of income during the year. The reduction of water resources resulting from snow melting has affected the amount of agricultural and garden production, as well as the volume of environmental water in the rivers. In the current research, the amount and trend of changes in the snow mass in the snow catchment areas of the Alborz and Zagros mountain ranges during a period of 42 years were studied. Zoning maps of water equivalent to snowmelt were produced using MERRA2 satellite model data and in the geographic information system environment. The results showed that the highest amount of water equivalent to snowmelt in January (14.15 liters per square meter) is observed in the central Alborz region to the northwest of Iran (Alborz) and the Zardkoh Bakhtiari region .