The rate of fall is sufficient to reduce cyclonic action appreciably, thus reducing the effectiveness of the mechanism that causes precipitation. This phenomenon also reduces precipitation in the Prairie Pothole Region of the Dakotas. The southern part of the region has more precipitation because it receives more moisture-laden airmasses from Gulf of Mexico. Annual precipitation in the region ranges from 33 cm in northwestern North Dakota to 58 cm in southeastern South Dakota. Larger amounts of spring and summer precipitation in the southeastern part of the region account for most of this difference.
Reduced visibility is caused by snow, blowing snow, or mixtures of snow and soil.
North and South Dakota have a far greater frequency of blizzards than any of the adjacent states. Snow from February and March blizzards and snowstorms is often an important source of spring runoff for prairie wetlands. Brief heavy rains occur more frequently than in the arid west, but are only rare or occasional compared to the southeastern United States and the gulf coast.