Here is another image from the same site about the Chinook or foehn
effect winds taking dust out to sea:

Glacial sediments can form dunes along Alaskan river valleys. Chinook
winds, push the glacial sediment toward the sea. These intense, warm
winds blow down mountain valleys, often taking the glacial silt with
them.

Because their primary movement is downward rather than lateral, these
downslope winds can change direction with the mountain valleys they
travel.

http://earthobservatory.nasa.gov/New...3?img_id=17453