Glacier begin to from when more snow falls during the winter than melts and evaporates in summer. The excess snow gradually builds up in layer. its increasing weight causes the snow crystals under the surface to

After a rainfall, water fills the stream channels called wadi  1. The rapidly flowing water cuts away the rocks of desert mountains and carries sediments created fan-shaped known as alluvial fans 2. Sometimes, the streams carry water into low areas in the desert plains and form into temporary lakes. The water that collects in these lakes either evaporates or seeps into the ground. Water erosion also creates big flat-topped hills known as mesas 3. and smaller flat-topped hills called buttes 4.

Erosion is the natural process by which rock are broken loose from the Earth,s surface at one location and moved to another. Erosion changes land by wearing down mountains, filling in valleys, and making rivers