In the aftermath of the Sunflower Fire, locations downhill and downstream of the burned area are now more susceptible to flash flooding and debris flows if and when storms move over the area.
A brief period of moderate rainfall is normally absorbed into the soil. But after a fire, the rain quickly runs off because the vegetation has been charred or destroyed, and severely burned soils act like pavement and repel the water. As a result, runoff from storms will be greater, with a heightened risk for flash flooding.
Water flowing down steep hilly terrain can transport large amounts of ash, sand, silt, rocks and vegetation debris, and suddenly flow over the banks of creeks and washes. The force of the water and accumulated debris can damage or destroy culverts and buildings, inundate roadways and bridged crossings, and potentially increase the risk of injury or death to people in the area.
The Sunflower Fire severely burned a significant portion of the Sycamore Creek watershed. Once rain begins, as little as 10 to 15 minutes of moderate to heavy rainfall will produce flash flooding and debris flows. These flows will quickly impact the residents of Sunflower, especially those living or working in close proximity to Sycamore Creek.
A significant flow of water and debris in Sycamore Creek may travel as far as 15 to 20 miles south of the community of Sunflower, inundating low water crossings of many forest roads. Heightened flow may persist in Sycamore Creek for hours after the rain stops.
In the event of moderate to heavy rainfall, do not wait for a flash flood warning in order to take steps to protect life and property. Thunderstorms that develop over the burned area may begin to produce runoff and flooding before a warning can be issued. If you are in the area vulnerable to flooding and debris flows, plan in advance. There will be very little time to react once the storms and rain start.
Heed the advice and recommendations from local law enforcement officials pertaining to road closures and any evacuation plans.
Monitor NOAA weather radio for all forecasts and statements and be prepared to take action should flash flood warnings be issued.