Page 108 - Super Earth Encyclopedia

ICE CAVES

MENDENHALL GLACIER

Glacier ice that forms high in the mountains creeps
slowly downhill until it reaches an altitude where the air
and surrounding rock are warm enough to melt it. This
makes a steady stream of meltwater flow from beneath
the end of the glacier. In Alaska, this melting process
has created long tunnels and caves in the base of the
Mendenhall Glacier. At this depth, the glacier ice is very
dense, having been compressed by the colossal weight
of ice pressing down on it from above. The dense ice
absorbs long-wavelength red light from the sunlight
that filters down into the cave, making its icy walls
and ceilings glow with a clear, luminous blue.

AT A GLANCE

• LOCATION Southeastern Alaska
• GLACIER LENGTH 13.7 miles (22 km)

• GLACIER STATUS Retreating because
of climate change
• ICE CAVES Fast melting away

STATS AND FACTS

GLACIER SOURCE FROZEN TREES
The caves beneath
Mendenhall Glacier Mendenhall Glacier Melting ice has
is one of the 38
revealed tree
have formed in ice large glaciers that stumps frozen
created from snow flow from the for more than
1,000 years.
that fell on Alaska’s AREA Juneau Icefield. At 1,500 sq miles (3,885 sq km),
Juneau Icefield
FROZEN WORLD AGE OF CAVE WALLS sq km 1,000 largest icefield in North America.
many centuries ago.
the Juneau Icefield is the fifth
2,000
3,000
1,500
1,000
500
sq miles
UP TO
250
YEARS
OLD
106

US_106-107_Mendenhall_Cave.indd 106 01/03/17 1:38 pm