Erosion, flooding, and formation of rough ice While standing on the Tanana River one mile below Wenrich Slough, Sam Demientieff and William Demoski discuss erosion, flooding, and formation of rough river ice. Process Observed: Rough IceBank ErosionFlooding Date Process Observed: Monday, December 17, 2007 Galleries: Tanana River, 1 mile below Wenrich Slough Gallery