An ice deposit on Mars could hold as much water as Lake Superior
A huge pool of water is frozen deep under the surface on Mars. It is approximately the same size as the largest of the Great Lakes-- Lake Superior. Scientists observed the mid-north latitudes in the Utopia Planitia region with over 600 passes of the orbiters ground piercing shallow radar, called SHARAD for short. This deposit is fairly bigger than the state of New Mexico, and its thickness ranges from 80-170 meters (or 260- 560 feet).
This deposit is composed of a 50-85% ice mixed with dust or rocks. The surface of Mars is too cold and far away from the sun for liquid water to exist, so it takes ice form. When it does get heated up, the thin and dry atmosphere turns the water into water vapor immediately. Today Mars has an axial tilt of 25 degrees, so the water accumulates near the poles. The tilt means that the equator is closer to the sun, so the water melts and goes away from the middle and toward the poles.
Scientists are saying that we could mine the water from Mars if we ever run out on Earth. In this plain they observed that the ice is very close to the surface, which makes it easier to mine. It is also in a relatively flat area and is at a low altitude which would make it easy to land a spacecraft on.