Snow avalanche risk management in Shemshak region: a modelling, mapping and evaluation of factors affecting the occurrence of snow avalanches

In the last two decades, 40 persons have been killed by avalanches in the Shemshak region, Tehran, Iran. The area has also suffered a lot of damage. Here, we have studied 18 variables affecting the occurrence of avalanches in Shemshak region. They are related to the geomorphological, topographic, climatic and snow conditions as well as human activities. The modelling and mapping were performed using various environmental factors and statistics as well as data-driven methods (e.g. hierarchical analysis method, maximum entropy) followed by field visits. Finally the conceptual model of avalanche risk assessment was prepared using spatial mapping and HEV approaches. The results showed that avalanche hazard maps differ from the risk maps. Many areas that were considered as low- or medium-hazard areas in avalanche hazard maps are considered as the high-risk and most important areas in the avalanche risk map. Also, some high-risk areas in the avalanche hazard maps are considered as low-risk areas in the avalanche risk map. Based on the obtained results, it can be concluded that due to the complexity of the risk mapping process, it is difficult to use a worldwide benchmark and indicators system to assess hazards and prepare risk maps. Therefore, more research is needed to elucidate the applied risk maps for avalanche hazard management.