Mix one-quarter cup of flour with 1 cup of cold water. Stir well until there are no lumps. Add 5 cups of boiling water. Heat paste in a pan over the stove until it thickens, about 15 minutes, stirring occasionally. Remove the paste from the stove. Stir in one-quarter cup of salt.
Crumble enough sheets of newspaper to cover most of the surface of an 18-inch by 18-inch plywood board with newspaper balls. Tape the newspaper balls in place with masking tape. Tear 2-inch strips of newspaper and magazine paper and dip the paper strips into the paper-mache paste. Pull strips out one at a time and squeeze out excess paste between your fingers. Cover the layer of newspaper balls with the strips and smooth on. Allow 24 hours for the formation to dry. Store the excess paste in an airtight container.
Add another layer of newspaper balls to the dry paper-mache foundation, smaller than the layer before it. Cover the new layer of newspaper balls in coated strips and allow 24 hours for this layer to dry. Continue adding smaller layers until the mountain has reached the desired peak.
Paint the mountain with acrylic paints. Paint the base green representing the vegetation growing there, the middle of the mountain brown representing the area beyond the timberline, and paint the top of the mountain white representing the mountain peak.