There’s been a lot of ash sifting, both literal and figurative, in the wake of California’s Station Fire. Along with information about how the fire and firefighting methods affected humans and animals, two more serious issues have emerged—the specter of landslides almost certain to come and the U.S. Forest Service’s possible role in leaving large swathes of land prone to such danger.

The U.S. Geological Survey estimates a greater than 80 percent chance of debris flows in five regions burned by the Station Fire, according to an emergency assessment released Tuesday. The assessment is based on models of how 678 drainage basins in the burned area would react to a three- and a 12-hour rainstorm this winter.

Not only are mudslides likely , they could also be extremely large—up to 100,000 cubic yards—or enough cover a football field with mud and rock to about 60 feet deep—in each region, according to an article in the Los Angeles Times.

“Some of the areas burned by the Station Fire show the highest likelihood for big debris flows that I’ve ever seen,” USGS geologist and assessment author Susan Cannon told the Times.

The Station Fire, which raged in the Angeles National Forest during late August and early September, blackened nearly 250 square miles before it was contained. Now, federal officials are looking into accusations that the U.S. Forest Service might have let the fire grow out of control while trying to save on costs, according to another Los Angeles Times article.

The internal inquiry was sparked by residents’ complaints after a Times story indicating that Forest Service officials toned down firefighting efforts in the first days of the Station Fire. That, coupled with a Forest Service memo calling for limiting overtime and the use of contractors (i.e., state and local firefighters) , was interpreted as neglect, according to the article. Both Angeles Forest Fire Chief David Conklin and Los Angeles County fire officials—who have been criticized for withholding equipment requested by the Forest Service—have defended their actions, saying the nature of the fire, not budget concerns, affected their decisions.