This thesis presents an approach for modeling and simulation of a flowing snow avalanche, which is formed of dry and liquefied snow that slides down a slope, by using molecular dynamics and discrete element method. A particle system is utilized as a base method for the simulation and marching cubes with real-time shaders are employed for rendering. A uniform grid based neighbor search algorithm is used for collision detection for inter-particle and particle-terrain interactions. A mass-spring model of collision resolution is employed to mimic compressibility of snow and particle attraction forces are put into use between particles and terrain surface. In order to achieve greater performance, general purpose GPU language and multi-threaded program-ming is utilized for collision detection and resolution. The results are dis-played with different combinations of rendering methods for the realistic re-presentation of the flowing avalanche.