Weathering
The breaking down of rocks and other materials on the Earth's surface.
Permafrost
permanently frozen layer of soil beneath the surface of the ground
Sinkholes
formed when a cavern loses its support and the ceiling caves in
Erosion
the process by which water, ice, wind, or gravity moves weathered rock and soil
Stream
a channel along which water is continually flowing down a slope
Flood plain
flat land near the edges of rivers formed by mud and silt deposited by floods
Meander
a curve in a stream
Delta
flat plain of mud or sand between branches of a river
Glaciers
a large mass of sloving ice and snow that carves new features and deposits sediments
Glacial drift
the rock material carried and deposited by glaciers
Moraines
the piles of rocks, sand and soil that form ridges made by glaciers
Desert
An extremely dry area with little water and few plants