Deposition of wind blown snow forms large drifts that hamper winter travel. In mountainous regions, cornices and wind depos- ited snow inthe leeof ridgestrigger avalanchesthatdamage structuresand transport systems. Effective control of these natural phenomenonrequires a better understandingof the physical processes in blowing snow. Wind transports snow by three mechanisms.
Particles roll along the surface in a process termed creep.
This mechanism occurs in light winds and accounts for very little transport. Strong winds eject particles from the sur- face in a mode of transport called saltation. Particles in saltation bounce along the surface, rebounding to heights typically within 10 cm of the surface. Much of transport during blowing snow storms moves in saltation. In the thirdtransport mode, knownas suspension, particles travel without impact, at heightthat may extend severalhundred meters in polar storms.