The large (mean height 25m, spacing 300m), relatively straight-crested dunes of the central Oregon coast migrate an average of 3.8m/yr toward an azimuth of 26o. The dunes are transverse to the strong S-SW winter storm winds that are responsible for their basic form, orientation, and migration. The dry, moderate, N-NW summer winds modify the dune form but not the dune trend. Comparison of the sand transport, calculated from wind data and measured from dune migration, indicates that the actual transport by the wet southerly winds is only one-third of the amount calculated assuming dry conditions. The internal structures of the dunes confirm northward migration during wet conditions. A depositional model based on dune climbing predicts that the preserved record of oblique dunes formed by an obtuse-bimodal wind regime would consist of tabular sets of crossbeds in which the dip angles increase upward from the base of each set.-from Authors
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Storm-controlled oblique dunes of the Oregon coast.