Is The Ground in Denali Really
Frozen Solid Just Inches
Below The Soil?

This is an image of exposed Permafrost
(image from http://dana.ucc.nau.edu/~nlb5/)

  
Denali is full of
lush green plants.

Permafrost

At Denali National Park’s Visitor Center, we spoke to the Park Ranger, Ingrid.  She told us that Denali Park receives very little rain.  On average, Denali only gets about 14 inches of rain, about the same amount of rain that the desert area of Arizona gets.  

How can it be that Denali gets so little rain but is so full of lush green plants and has such abundant animal life?

The answer lies in the permanently frozen layer of ice that lies beneath much of Denali National Park.  This layer of ice is called permafrost.  In some areas of Denali, the permafrost is only 8 inches below the surface of the Tundra.  While in other areas, the top of the permafrost layer can be as deep as 11 feet.  Permafrost can be extremely thin, 1mm, or very thick, ¼ mile deep.  Look over here.  At this river bank,  you can see the very top of the permafrost where soil has eroded away.

This is an Image of Wet 
Tundra in Denali 

Permafrost is Impermeable

This layer of permafrost is impermeable to water.  The permafrost traps all water near the surface of the earth.  As the warm summer sun melts some of the permafrost, the ice melts to water and is trapped on top of the remaining permafrost.  As the summer rains fall on Denali, the water soaks into the tundra but cannot penetrate the permafrost.  The rainwater is trapped on 

So, You Want To Learn More About Alaska's Permafrost?

Frozen ground in the Arctic
http://www.r7.fws.gov/nwr/arctic/permpics.html

What is Permafrost?
http://sts.gsc.nrcan.gc.ca/permafrost/whatis.html

What is Permafrost?
http://www.permafrostalaska.com/whatpermafrost.htm

Indicators of Permafrost
http://www.permafrostalaska.com/wherepermafrost.htm

Try This (Hands-On Fun)

Permawhat?
http://www.pbs.org/edens/denali/permawht.htm

What is permafrost?
http://www.ktca.org/newtons/11/prmfrost.html