Plate 1: MOSES LAKE — Lake dammed by wind-blown sand
Moses Lake in central Washington was formed by damming of Crab Creek by wind
blown sand. The area is a,dry plaiq in the rain sDadow of the Cascade Mountains. Sand is
blown from a soulhwesterly to 'Wesfe.rly direction (lower side of stereogram). The lowland
of the former Crab Creek valley is fairly deeply coodkbd with sand (lower half of stereo-
gram), the dunes overlapping one another somewhat like the scales Of a fish. On the
upland beyond the valley the sand is less plentiful, and some dunes show the pattern of
barchanes, crescents with the convex side to the wind (B.O - 4.5), but many are advancing
as U-shaped dunes with the inside of the U windward (D.O - 4.0). As the sides of the
U-shaped dunes lengthen, they tend to form straight dunes elongate in the direction of
wind (C.o 3.9).