The landscape of Rocky Mountain National Park is the steepest in the United States. Sixty mountain peaks over 12,000 feet high result in world-renown scenery and provide challenges for hikers and climbers. The extreme topography creates an amazing range of ecological zones within a short distance, similar to the changes that would be seen in a drive from Denver to northern Alaska.The continental divide, which runs north - south through the park, marks a climatic division. The western slope, due to prevailing winds, receives more precipitation than the eastern slope. (The town of Estes Park averages 13.1 inches of precipitation; the town or Grand Lake 19.95 inches per year.)
Although many visitors think of the park as pristine, humans are having a marked impact on its environment. Airborne pollutants from vehicles, factories, and agricultural activity are altering soil and water chemistry. These changes in the physical environment are in turn altering biological communities. Inputs are most significant on the east side where upslope winds, blowing from the communities and agricultural areas of the Front Range, bring nitrates, mercury, ozone, sulfates, and other compounds to the park. Rapid development from Fort Collins to Pueblo make it likely that these pollutants will continue to increase. Other toxins come from far away. Research has shown that alpine lakes are particularly vulnerable to persistent organic pollutants (POPs) such as DDT. These compounds evaporate over tropical areas, then fall out in cooler, temperate areas, a process known as global distillation. Once deposited in high elevation lakes, cool temperatures prevent POPs from regaining their gaseous state and they continue to accumulate.