Abstract:At the beginning of 2008, persistent large scale of ice and snow weather hit Zhejiang Province. With the support of remote sensing and geographical information system (GIS) technology, a deep study on the genesis, developing and melting of snow was carried out. First, snow and cloud were distinguished well using MODIS data, and a snow model (normalized difference snow index) was established to extract the snow information. Then, spatial and quantitative analyses on the distribution of snow cover were conducted, and the melt character was studied through the snow cover depletion curve. Finally, a preliminary assessment of the disaster of forests was discussed using the method of ΔNDVI. The results show that snow melt has a decreasing trend of minus exponent. Originally, the snow cover ratio at the middle altitude (300-900 m) could reach over 70% and was more than that at altitudes higher than 900 m or lower than 300 m. Meanwhile, the disparities in the different elevation zones became narrower along with the snow melting. The speed of snow melt slowed down significantly as before. On Feb.16, snow cover was consistent with the terrain character, that is, the higher the elevation is, the greater the snow cover is. When most snow is distributed in the high mountainous area, the speed of snow melt is much slower as before. Until Feb. 29, there was no snow at the study area. The degree of disaster is related to the time of snow cover and the elevation of the forest area. Working at real time monitoring, dynamic analysis and disaster assessment of snow cover in South China is very important to the disaster prevention and reduction of local government.