ABSTRACI:. Slash burning is a common site preparation technique used after timber harvest throughout the Southeastern United States. Little quantitative information exists on the hydrologic response to burn severity. This study compared the effects of low‐severity and high‐severity burns on runoff and sediment yields during rainfall simulation and during natural rainfall in the Southern Appalachian Mountains. Fire severity was largely determined by moisture conditions of the forest floor prior to ignition. Runoff and sediment yield variability was high between plots within the same treatment area due to differences in forest floor characteristics and infiltration rates. Conditions of high‐severity resulted when burning was conducted with relatively dry fuels. Sediment yields were 40‐times greater for the high‐severity treatment areas than the low‐severity treatment areas.