Sioux Falls, South Dakota – Fires could spread rapidly within minutes this afternoon as wind gusts near 30 mph combine with humidity levels dropping as low as 18 percent across southeast South Dakota and northwest Iowa.
According to the National Weather Service in Sioux Falls, a Red Flag Warning is in effect through the evening for areas along and near the Missouri River Valley, including Sioux Falls, Yankton, and Sioux City. Peak conditions are expected between 1 p.m. and 8 p.m., when southwest winds strengthen and relative humidity sharply declines.
Communities such as Mitchell, Vermillion, and Spencer will see sustained winds between 15 and 25 mph, with stronger gusts capable of pushing any spark into fast-moving grass fires. Dry vegetation and unseasonably warm temperatures will only intensify the risk.
Officials urge residents to avoid outdoor burning and use extreme caution with grills, farm equipment, and vehicles parked on dry grass. Even small ignition sources can lead to uncontrollable fires under these conditions.
The chances will begin to ease after sunset as humidity levels recover, but elevated concerns may continue into Sunday. Additional warnings could be issued if conditions persist.
