Understanding Albedo & Aspen Leaves On Snow

A few years ago, while hiking on a partially snow covered trail at about 9,000 feet in October, I noticed Aspen leaves had fallen onto the snow. Some of those leaves lay on the surface of the snow while other leaves appeared as if they had pushed the snow down in a manner exactly representing the shape of the leaves. 

Of course a single Aspen leaf is not heavy enough to compress the snow. It appeared to me that the leaves had absorbed enough sunlight to heat and melt the snow resulting in a depression in the snow with the leaf on top of the depression.

This of course is on a tiny scale what is happening in places like Greenland. The term albedo refers to the ability of a surface to reflect light. Pure clean snow has a very high albedo whereas snow covered with millions of soot particles has a much lower albedo and in fact in the summer many of these places actually melt holes in the ice creating uncountable  pools of water. 

I recently viewed the movie Chasing Ice and the photographer/scientist James Balog. He photographed many of those holes along with the dirt they contained. 

His website is http://extremeicesurvey.org/