Ice chokes the Great Lakes in these Moderate Resolution Imaging Spectroradiometer (MODIS) images from the Aqua satellite on January 27, 2003. Pictured (left to right) are Lakes Huron, Erie, and Ontario. It is not unusual for portions of the lakes to freeze in the winter; for example, 90 % of Lake Erie is typically frozen during normal winters. The Great Lakes have probably never frozen over completely due to their size and depth. In the false-color image, snow-free ground is green, and snow and ice are bright blue. Open water in the lakes appears deep blue.