EPOW - Ecology Picture of the Week

Weather on the Mountain

Cap clouds over Mount Adams, Washington USA

Explanation:  Shielded in layers of clouds is the immense dormant volcano called Mount Adams in southern Washington state.  Mountains this immense create their own weather, especially when they form a rainshadow as does this mountain as part of the Cascade Range that runs from Canada to California.  

On this late autumn afternoon, cool air blowing over Mount Adams has condensed to form what is called cap clouds, also called orographic clouds (orography is the study of mountains).  

Mountain weather can greatly affect the kinds of vegetation and wildlife that live on its slopes.  As temperature and precipitation change by elevation, they create what the 19th century ecologist C. Hart Merriam called life zones -- ranging from moist mixed deciduous-conifer forests in the valley lowlands, through cold conifer forests higher up, to subalpine and alpine environments toward the peak of such tall mountains as Mount Adams.  Each life zone has its unique assemblages of species.  How life zones might alter under changing climate is a matter of research interest.  

For now, though, enjoy the beauty of mountain weather.