The Mustang Fire burn scar is located just north of the Salmon River in central Idaho, in which the fire burned 340,700 acres of land during October of 2012. As a result, flash flooding, debris flows, and rock slides have become a major concern for several drainages that were affected by the fire. The four major watersheds affected by the Mustang Fire are the Colson Creek, Owl Creek, Spring Creek, and Indian Creek drainages. Heavy, intense rainfall that occurs over these areas could result in flash flooding, which could ultimately impact homes, campsites, and roadways at the mouth of these creeks. Pictured here is a portion of the Mustang Fire burn scar, taken not long after the fire was contained. You can see here the immensity of the burn, which burned all vegetation in its path, leaving very little behind to soak up future rainfall. So what type of rainfall is necessary for burn scar flash flooding? The main type of rain is high intensity rainfall produced by thunderstorms, either from individual thunderstorms, or a line of thunderstorms training over the burn area. This could definitely produce a flash flood scenario. For the Colson Creek and Owl Creek drainages, one half inch of rain in 30 minutes or less could produce flash flooding. For Indian Creek and Spring Creek, the threshold will be between 0.3 and one half an inch of rain in 30 minutes or less. The other type of rainfall that could occur over the burn area will be stratiform rainfall. This will be a prolonged period of steady rainfall, which could last a few days. If this occurs, it will NOT yield a flash flood scenario. Why? Because we NEED high intensity rainfall. This is the most important thing to remember. Here is a video showing a flash flood that occurred over a different burn area, but simply depicts the intensity of flash floods that result from burn scars. Now let๏ฟฝs talk specific f a thunderstorm producing heavy, intense rainfall occurs over the Colson and Owl creek watersheds, flash flooding is likely to occur. We will take a look at specific threats and areas of most concern, should these areas experience flash flooding. Here is a Google Earth image of both the Colson Creek and Owl Creek drainages. Thunderstorms during the early summer of 2013 produced intense rainfall over this portion of the burn scar. Here is an example of flash flooding that occurred near Colson Creek. You๏ฟฝll notice the large rock flow that covered the dirt roadway. Here is a picture of flash flooding near Owl Creek. One more example of flash flooding that occurred near Owl Creek. Next, let๏ฟฝs move to the east and address the flash flood potential near Spring Creek and Indian Creek. Here is a Google Earth image of the Spring Creek drainage. Notice the steep terrain surrounding the creek, whose rainfall runoff could potentially cause Spring Creek to flood. The creek is depicted here by the red line. Should flash flooding occur, runoff and debris will flow out of the mouth of Spring Creek, ultimately reaching the Salmon River. Flash flooding could affect Salmon River Road, as well as the campground near the banks of the Salmon River. Now we๏ฟฝll take a look at the Indian Creek drainage, where flash flooding is also possible. Again, the steep terrain involved in the burn scar area near this creek could cause rock and debris flows in addition to flash flooding. Indian Creek is pictured here by the red line. Homes and roadways at the mouth of Indian Creek could be impacted by flash flooding. If rock or debris flows also occur, Salmon River Road could be impacted, and could be closed for a time, depending on the severity of the debris/rock flow. If you have any questions or concerns involving the Mustang Burn area or its flash flood potential, do not hesitate to contact us here at the National Weather Service office in Missoula, Montana. Call us 24 hours a day, 7 days a week, even on holidays a 06-329-4840, or visit our websit ww.weather.gov/missoula