Solifluction or Solifluxion is an errosion process that occurs in areas with a perma-frost. During the winter the whole thickness of the soil is frozen.

During the summer the top layer of the soil will melt. The ice below it acts as an impermeable membrane, not allowing the melted water in the surface layer to drain away.

This surface layer becomes supersaturated with water and with no vegitation to hold it together it will slump.

The gentle flow of the material will tend to align rocks to the direction of flow.