time ago glaciers covered what is now the Matanuska Valley in Alaska.
For many thousands
of years meltwaters from the Matanuska Glacier fed the Matanuska River, which has carved a winding channel through
the Talkeetna and Chugach Mountains. The foot of the Matanuska Glacier is a great pile of silt and
during the summers the river is a gray color, like city sidewalks.
The gray is silt from the glacier. The
river flows through a wide channel which is a thick bed of very
fine, glacial silt. In the winter the glacier doesn't
melt very much, so the river flows a clear green or deep blue color.The
winter wind called the Matanuska flows along the river channel and
when it reaches a sufficient speed, it picks up silt from the dry
parts of the river bed. This silt becomes suspended, flowing
many miles on air currents until some resistance
to air flow is reached. On the leeward side of trees you can often
see drifts of silt
A benefit is renewal of top soil. Click on "Zoom In" to
view the silt shadow beneath the willow. The Matanuska
Wind can also be detrimental to the land, stripping top soil from unprotected fields once
any snow cover has blown away. Return
to Winter Winds.