The Landslide in Your Backyard

As climate change brings more intense rain to the mountains, dangerous debris flows are on the rise

- BY JEN SCHWARTZ | ILLUSTRATION BY MARK ROSS

THE LANDSLIDE BEHIND MY NEIGHBOR'S BACKYARD doesn't exist—not according to the New York State landslide map or Greene County's hazard-mitigation plan or the federal inventory managed by the U.S. Geological Survey. But when you're standing in the middle of the debris field, the violence of the event is still evident 14 years after it occurred. The fan of the landslide, where a surge of boulders and mud blasted the forest open after rushing down the steeper slopes of Arizona Mountain in the Catskills, is about 100 feet wide—an undulating plane of rocks, mangled tree trunks, and invasive plants such as Japanese stiltgrass that thrive in disturbed areas.

On a hot July day the seasonal stream that runs through this ravine, named the Shingle Kill, is small enough to step over. When Tropical Storm Irene hovered over these mountains on August 28, 2011, the Shingle Kill swelled like all the otherwise unremarkable streams in the area, frothing downhill in a torrent the color of chocolate milk. This storm was a particularly bad one, dropping up to 18 inches of rain on the northeastern escarpment of the Catskills. Throughout the region explosive rivers eroded their banks, flooding towns and ripping away buildings.

The first house the Shingle Kill passes as it emerges into our community belonged at the time to Diane and Ken Herchenroder, who had lived there for nearly three decades. In the past, when the Shingle Kill occasionally raged, they could hear rocks colliding in the streambed. But this time it was louder—and faster.