Rapid City, S.D. – Thick fog has settled across a wide stretch of the Northern Plains early Wednesday, reducing visibility to less than a quarter mile from eastern Wyoming into South Dakota and western Nebraska. The National Weather Service has issued multiple Dense Fog Advisories covering parts of all three states through late morning, warning of hazardous travel on major highways.
According to the National Weather Service offices in Rapid City, Cheyenne, North Platte, Aberdeen, Billings, and Las Vegas, dense fog will persist through 10 a.m. CDT (9 a.m. MDT) for most South Dakota counties, including Mellette, Todd, Tripp, and Pennington, and through noon MDT for Cheyenne and Scotts Bluff counties in Wyoming and Nebraska. The fog zone also extends north into Corson, Dewey, and Jones counties near Pierre, S.D., and as far west as Carter and Powder River counties in southeastern Montana.
Drivers along I-90, I-25, U.S. 85, and U.S. 83 should expect rapid changes in visibility and slow-moving traffic. Law enforcement urges motorists to reduce speed, use headlights, and leave extra following distance. The dense fog may also affect early flights and school bus routes in Rapid City, Cheyenne, Valentine, and Chadron.
Conditions will gradually improve by late morning as temperatures rise and light winds mix out the fog. Clearer skies are expected by afternoon, though another round of patchy fog could redevelop overnight in low-lying valleys and river corridors.
