An extraordinary wind storm on December 20, 1977, caused moderate to severe damage to structures, crops, orchards, vehicles, wildlife, and soils in an area of about 2,000 km² in the Southern San Joaquin Valley, California. Wind that may locally have reached velocities of 300 km/hr mobilized more than 25 million metric tons of soil from grazing lands alone within a 24-hour period, yielding a depositional plume that extended at least to the northern end of the Sacramento Valley; comparable amounts of soil may have been displaced in adjacent agricultural lands. The wind-stripped land in the Tehachapi and San Emigdio mountains caused accelerated runoff during ensuing rainstorms that exacerbated the problem of flooding in the southern valley and initiated numerous gullies that will continue to extend the loss of soil.

The principal factors contributing to the severity of the storm’s impact were drouth, overgrazing, and the general lack of windbreaks in the agricultural land. Vegetation in the grazing lands bordering the valley showed the combined stresses of drouth and grazing before the storm and provided little forage and only slight protection to the soil. Broad areas of agricultural land had recently been plowed in preparation for planting, and additional areas had been stripped of natural vegetation and leveled in preparation for agricultural uses making them vulnerable to wind erosion. Other quantitatively less important contributing factors included stripping of vegetation for urban expansion in the Bakersfield area, extensive denudation of land in the oil fields north of Bakersfield and elsewhere, and local denudation of land by récréation vehicles.