Sioux Falls, S.D. – Any spark along I-90 west of Mitchell could spread rapidly between noon and 6 p.m. Sunday as southwest wind gusts reach 30 mph and humidity drops as low as 15%, creating critical fire weather conditions across south-central South Dakota.
According to the National Weather Service in Sioux Falls, a Red Flag Warning is in effect from 12 p.m. to 6 p.m. CST for areas west of Forestburg to Mitchell and Wagner, including Lower Brule, Chamberlain and Winner. Near-record high temperatures combined with very dry air and breezy south-southwest winds will produce high to very high grassland fire danger.
The most critical conditions are expected during the mid-afternoon hours when winds peak and humidity bottoms out. Open fields along I-90, rural stretches of SD-50 and areas south toward Lake Andes are particularly vulnerable. Any outdoor fire could spread quickly and become difficult to control.
Residents are urged to avoid all outdoor burning, properly discard cigarettes and secure trailer chains that could create sparks along highways. Farmers and ranchers should delay fieldwork that could generate heat or sparks during the warning window.
Conditions will gradually improve after 6 p.m. as winds ease and humidity begins to recover, but elevated fire danger may persist into early evening. Additional advisories could be issued if winds strengthen or humidity falls lower than expected.
