عنوان مقاله [English]
Snow avalanche is one of the phenomena in snowy and mountainous areas that may result in hazards and irreparable problems. The objective of this study is to determine the most important effective factors in avalanche events in Meigoun-Shemshak road. Meigoun- Shemshak road has been located in Shemshak drainage basin with an area of 37.75 Km2 in Roodbar Ghasran district, Shemiranat County, Northeast Tehran. To assess avalanche corridors, effective environmental parameters on avalanche including length of valley, width of valley, azimuth, slope percentage, valley curvature coefficient, elevation, clay, silt, sand, roughness coefficient, vegetation and rock cover percentage, precipitation, temperature and snow were determined. In the studied area, three types of valley were identified: ephemeral avalanche valley, permanent avalanche valley, without avalanche valley. The environmental parameters comparison between ephemeral avalanche valley and permanent avalanche valley showed that slope percentage, roughness coefficient, clay, silt, sand, vegetation and rock cover percentage are significant in the valleys and also in comparison between the sections of them only valley curvature coefficient was significant. In comparison between three types of valleys, parameters: Azimuth, valley curvature coefficient, slope percentage, surface roughness, vegetation and rock cover percentage were significant. The results of comparison between sections of the three types showed valley curvature coefficient was the significant parameter. The most important parameters affecting the avalanche are Azimuth and surface roughness coefficient.