Monsoon rainfall over the Ferris Fire burn area has moved rocks, branches, mud and other debris through parts of the watershed, as specialists assess how the fire altered soils and runoff across the landscape.
Shauna Jensen, a Burned Area Emergency Response team leader and hydrologist, recently toured portions of the burn area with KSJD. Along Lone Dome Road, Jensen pointed out debris that moved out of a mostly burned watershed during recent rains. She cautioned that heavy rainfall could have caused some debris movement even without the fire. But wildfire can change how fast water moves across a landscape and the amount of material it carries downhill.
BAER teams evaluate soil stability, roads, recreation areas and the potential for the spread of invasive plant species. Jensen demonstrated areas of low, moderate and high soil severity within a short distance of each other. In the more severely burned ground, most of those we saw were under former slash piles from logging operations, she found brittle roots and soil structure damaged by heat.
“We see some fine roots, but they’re going to be brittle, so they’re going to break and pull apart out of the soil pretty easily,” she said of a patch of soil that had been more severely burned in the fire. “ Our soil structure is all kind of disintegrated. So we’ve cooked this pretty good.”
Specialists begin their assessment with satellite imagery comparing conditions before and after a wildfire, then site visits at locations on the ground to examine how badly soils have actually burned. Those determinations are used to map the burn’s severity and help identify places vulnerable to damaging runoff in the post-fire watershed.
“When you have a 70,000-acre fire, you can only treat so much. You don’t know where the storm is going to end up,” she said.
Jensen said BAER teams generally do not attempt to treat entire burned hillsides, like in the past. Instead, current operations focus on protecting specific homes, roads or other assets threatened by debris flows or other hazards that linger when the fire is out.
The effects have also reached the Lower Dolores River. Dolores Water Conservancy District General Manager Ken Curtis said rain after the Ferris Fire carried mud and ash into the river. The Ferris Fire was downstream of McPhee Reservoir, which holds water used for agricultural and municipal purposes, and did not directly affect the Dolores Project, but Curtis said the Lower Dolores fishery is among his main concerns.
Recovery has already started beginning in some areas with flashes of green across the landscape. Jensen pointed to new growth in riparian areas, while Colorado Parks and Wildlife biologist Jamin Grigg said wildlife like deer and elk can return relatively quickly where vegetation starts to sprout.
“We should see a lot of fresh green-up, especially with these monsoon rains that we’re getting… That’s going to draw wildlife, and especially grazers and herbivores, browsers such as deer and elk, right back into those areas,” said Grigg.
Those areas with more severely burned spots may take substantially longer to recover.
For BAER teams, the primary task is determining where fire changed the landscape enough to create new risks and where something downstream can realistically be protected.
