Grand Teton National Park, Wyoming. Morning light illuminates 12,605’ Mount Moran above Leigh Lake in the Teton Range of northwest Wyoming. Leigh Lake was created when a large glacier flowed down Leigh Canyon during the Pleistocene epoch. As it deposited piles of rock and debris at its foot, the resulting terminal moraine blocked the flow of the stream and formed this lake. Jenny Lake, located just to the south, was formed in the same manner as a glacier flowed down Cascade Canyon.