GNA - Ecology of the Great Plains
Map of the Great Plains - by Me! This vast sea of grass stretches from the foothills of the Rocky Mountains in the west to the Mississippi River. Its northern limits are marked by the Saskatchewan River, at which point the landscape is dominated by the rolling forests of the Laurentian Shield and the Mackenzie River valley. In the south, its transition to desert scrubland is marked by the course of the Red River. Pointing Them North - Olaf Wieghorst The region is semi-arid and temperate, growing more tropical as one moves southeast. This transition is marked by increased precipitation, though across the region most rainfall is between May and July. Both short- and long-term droughts are common. Summers tend to be hot, averaging 35 C in the south and 17 C in the north, while winters are cool, hovering around 15 C in the south and hovering around freezing in the northern portions. That said, the region's flat and open nature can cause large and unpredictable swings in temperature fr