Morning
Edition, October
17, 2007 · Water
levels in the three upper Great Lakes are wavering far below normal, but Lake
Superior, the northernmost lake, is already at a record low for this time of
year. The problem comes in the balance between precipitation and evaporation:
lakes evaporate in fall and winter. But with too little ice cover to cap off the
lake, excess evaporation occurs.
Ice Cover on
Lake Superior (also scroll down to see evaporation & lake effect snow)
(MODIS satellite image from http://www.ssec.wisc.edu/~gumley/modis_gallery/
)
High evaporation and lake effect
snow from Lake Superior
