Rugged and isolated, the Rubicon River Valley on the border of El Dorado and Placer counties was for many years an idyll of old growth trees and icy swimming holes. Then the King fire roared through last month, turning a 20-mile stretch of the canyon into a vast dead zone of ashen earth and smoldering stumps.
Experts now worry that the devastation and the extreme temperatures of the fire, which scorched much of the soil and reduced its ability to hold together and absorb runoff, could lead to floods and mudslides when winter storms arrive. The same conditions affect parts of the south fork of the American River near Pollock Pines, where an arsonist allegedly started the 98,000-acre King fire on Sept. 13.
Members of the U.S. Forest Service’s Burned Area Emergency Response team, or BAER, swooped in last week, as the fire was finally contained, to assess the immediate dangers remaining in its aftermath. Members include botanists, hydrologists and geologists. Their job is to deal with such immediate threats as falling trees and crumbling roads.
BAER coordinator Eric Nicita said possible mudslides are a major concern, because when the top layer of soil cooks, it looses the fungi, bacteria and other organic material that hold it together and allow it to absorb water. In these conditions, rain runs through soil and tears it down instead of percolating into the earth.
“The only thing the water can do is roll downslope,” said Nicita, a soil scientist with the Forest Service. “All of a sudden, your flow is increasing incredibly.”
One of the most vulnerable danger zones from the King fire is the White Meadows Road area above the south fork of the American River, along Highway 50 near Fresh Pond. That’s where a dozen homes burned and where residents are already busy clearing dead trees and starting to rebuild.
The steep slopes were burned to ash, meaning the residents there still face the possibility that their temporary shelters and partially rebuilt homes could tumble down the hillsides in heavy winter rains.
New signs at the end of driveways last week warned trespassers to keep out or beware of dogs. Others asked the media to leave residents alone. A replica of an early American flag in front of one rural compound bore the likeness of a coiled rattle snake, ready to strike, and the motto “Don’t tread on me.” Tents have been erected in some lots. In others, RVs were parked where homes once stood.
In severely burned areas such as White Meadows, rockslides and mudslides remain distinct possibilities, Nicita said.
“People don’t know what’s coming down at them,” he said. “Those slopes can move.”
Residents should pay close attention to warnings from the National Oceanic and Atmospheric Administration and evacuate accordingly, he said.
About 20 miles northeast of the village of Georgetown, the Rubicon River canyon bore the worst of the King fire. Steep slopes there are scorched whitish-gray, indicating major soil damage. Stumps continued to burn last week after the fire was declared 100 percent contained. The wind wafted smoke through stands of blackened tree trunks.
Firefighters on the scene said the burning wouldn’t stop until rain and snow set in.
“On the northern portion, there were 30,000 acres of high-severity fire,” said Forest Service spokeswoman Dana Walsh.
There are few residents in the remote region, and the nearest populated downstream area is the rural community of Foresthill. The likelihood that flooding or landslides could affect it is limited, but the impacts on the natural environment are extreme, Walsh said.
The fire destroyed habitat used by black bears, foxes and skunks, among other creatures, requiring the animals to shift their territories to survive. For rural residents, that means, “You’re more likely to see a mountain lion in your front yard,” Walsh said.
Because thousands of trees died, there are fewer “straws pumping out water from the soil,” and natural springs will bubble to the surface, she said. That can be good in helping native plants grow in the wake of the fire, but invasive species can also spread quickly in fire-damaged areas.
Naturalists will try to discourage the growth of non-native star thistle and rush skeletonweed while encouraging the growth of native plants that help ecosystems recover.
“Certain (native) plants such as mariposa lily thrive on fire,” Walsh said.
Reforesting could go on for decades, she said. About 63,500 acres of the Eldorado National Forest were consumed by the King fire. Some areas will be replanted and others left to regenerate naturally. The area’s forests are a mix of ponderosa pine, sugar pine, Douglas fir, white fir and California black oak. The pines are most likely to be replanted, she said.
The BAER crew has just a week to assess the fire damage and file its report. After that, the Forest Service crews will go to work.
Helicopters will drop mulch on fire-damaged areas to prevent erosion, and ground crews will lay down wood chips and straw. Roads will be repaired where fire damaged culverts and bridges. Sensitive historical, cultural and American Indian sites will be protected from the heavy logging and earth-moving equipment needed for the job. Campgrounds where dead trees could fall will be logged.
But in many parts of the vast, burned territory, Walsh said, all crews will do is post hazard signs warning of possible falling trees and unstable ground.
Call The Bee’s Hudson Sangree, (916) 321-1191.