James and Bill Montivér had just finished boxing up their home on a steep road in Ketchikan, a fishing community turned cruise ship stop in southeast Alaska, when they heard a screech like a jet engine over the sounds of pouring rain.

Bill, who was scrubbing the kitchen cabinets, screamed and dropped to the floor as the house shook. In the next room, James was thrown from the couch into the ceiling, before crashing back down. The impact dislocated his shoulder; Bill fell into the basement as the kitchen collapsed from the force of the landslide.

Both men survived the wall of mud, rocks and trees the size of shipping containers that exploded into the almost 100-year-old home they’d planned to sell three days later. But one block away, a maintenance worker clearing storm water drains died when the earth slammed his truck off the road. Up the hill, a clean brown chute like a ski slope, cloaked on both sides by hemlock and spruce was left behind.

Over the past century, landslides in the state have periodically taken out power lines or disrupted roads. But until about a decade ago, they were rarely known to rip apart homes, and they were not commonly claiming lives in southeast Alaska. From 2015 to this summer, four deadly landslides struck some of the largest towns in the sparsely populated region — Sitka, Haines, Wrangell and then Ketchikan, in August — killing a dozen residents.

The region’s challenging landscape means housing is in short supply while emergency managers, forecasters and other experts encourage more towns to adopt hazard maps that show what land might be susceptible to sliding. The knowledge might save lives, but it could also limit what pockets of development are still possible.