In order to investigate the dynamics of powder snow avalanches, the experiment on fronts of gravity currents on the inclined wall is carried out. Experiments concerned are inclined thermals using saline water and turbid water into fresh water. The saline gravity current is conservative and turbid one is non-conservative. The speed and the maximum height of the front of gravity currents are measured for all cases. The salinity concentration profits are measured for the case of saline gravity currents. The non-dimensional speed of saline inclined wall plumes and thermals are nearly constant in the flow direction. On the contrary, the non- dimensional speed of turbid inclined thermal decreases in the flow direction.