Patchy Dense Fog this Morning... This is a special weather statement from the National Weather Service Office in Riverton. * WHAT...Patchy dense fog, with visibilities of a quarter to a half mile. * WHERE...Riverton, Hudson, Shoshoni and points along US Highway 20/26, Highway 220, the I-25 corridor and I-80 corridor. * WHEN...Through 11 AM this morning. * ADDITIONAL DETAILS...Visibility as low as a quarter to half a mile possible in some spots.