reticulate cryostructure
reticulate ice
reticulate-blocky cryostructure
retreat

retreating glacier
retrogressive thaw slump
ridge
ridge ice

ridging

ripple marks
river ice
river talik
rock flour
rock glacier

Frying Pan Glacier, Colorado, is almost entirely covered by rocks and debris in this photograph from 1966. (Photo courtesy of George L. Snyder, archived at the World Data Center for Glaciology, Boulder, CO.)
rotten ice
sail
saline permafrost
salinity
sand wedge
sand-wedge polygon
sastrugi
