EPOW - Ecology Picture of the Week

Virga on the Tanana

Rainstorm
Tanana River, Alaska

Explanation:  It is the brief summertime on the vast floodplain of the Tanana River in the boreal region of central Alaska.  

The Tanana River watershed hosts five species of salmon, and is popular for burbot and arctic grayling fishing.  

The name Tanana derives from the Athabascan word for "river trail."  Indeed, this river trail leads to the mighty Yukon River.   

      

Here, we see fingers of virga, which are curtains of rain that evaporate before they reach the ground.

The Tanana drains a watershed of nearly 46,000 square miles (74,000 sq km), and constitutes the vast Tanana River Management Area overseen by Alaska Department of Fish and Game.

 

For some years now, a main threat to local habitations has been regional warming and degradation of the permafrost.  

 

   

Information:
     Jorgenson, MT, CH Racine, JC Walters, TE Osterkamp.  2001.  Permafrost degradation and ecological changes associated with a warming climate in central Alaska.  Climatic Change 48(4):551-579.