Lake Erie’s shallowness not only makes it more prone to fluctuating water levels, but also enables this lake to freeze and thaw more readily than its neighbors.
Lake Jänisjärvi is a roughly oval-shaped lake, some 13 by 17 kilometers (8 by 11 miles) across, in northwestern Russia, near the Finnish border. The basin for this lake was formed hundreds of millions of years ago by a meteorite impact.