About 40 percent of the Decker Fire’s burn area is “moderately burned,” Burn Area Emergency Response (BAER) team leader Liz Schackenberg said, and about 1 percent is severely burned.
Schnackenberg said the greatest effects will be felt next summer and start declining after about three years.
The BAER team presented its findings on the Decker Fire to the U.S. Forest Service and local stakeholders last week.
Schnackenberg said the team’s focus was to look at imminent (within the next six-12 months) emergencies following the fire.
The team developed a burn severity map that examined how the fire affected the soils in the burn area. They looked to see how the fire affected ground cover and soil structure, Schnackenberg said.
The moderately burned portions are areas that have lost ground cover but have retained a lot of the soil structure. Those areas are spread throughout the fire’s perimeter, with significant portions in the northern half of the fire.
The whole fire is not going to have a big watershed response, Schnackenberg said.
The 1 percent considered severely burned has lost soil structure and roots. That means there’s nothing binding the soil together, she said.
An area of “concentrated response” is on the northeast corner of the fire, at the Chaffee/Fremont county line.
The change to soils drives watershed response, Schnackenberg said. If the soil loses structure, that makes flooding more likely.
She said the team also looked for hydrophobic layers, which occur when melted organic matter sinks into the soil and cools, forming a layer that water can’t penetrate.
Snowmelt probably won’t present much of an issue, Schnackenberg said, but short-duration, high-intensity rainfall has the potential to overwhelm the soil in the burned areas. That means an increased risk of flooding, runoff, erosion and debris flow during the summer monsoon season.
Some areas that haven’t had water flow previously will now have water flow during summer thunderstorms, Schnackenberg said, and areas that have been problems in the past will now be bigger problems.
One area in the north end of the fire on Methodist Mountain showed a 60-80 percent chance of debris flow given enough rain in a short time.
The team also looked at areas downstream that could be affected.
Schnackenberg said the team is also worried that the spread of weeds could be encouraged by the conditions.
Vegetation recovery will be slower in the severely burned areas, but overall should be pretty good.
Now that the team has presented its findings, Schnackenberg said, area agencies can formulate a plan to move forward.