USA: Looming landslide stokes fears, may help disaster predictions

By Shannon Hall

A crack is growing in Rattlesnake Ridge, a red-dusted hilltop near the town of Union Gap in Washington State’s Yakima County.

The fissure is causing a huge amount of ground perched above a small neighborhood to slip down. Since late October four million cubic yards of land have edged down the slope, raising the risk of a landslide. The failure point, geologists think, is approaching in the next weeks or months. So residents have had to make a decision: Do they abandon their homes for safety or risk their lives and stay? The decision is made more difficult by uncertainty about the path. Though the slide is likely to bypass the nearby houses and simply dump into a quarry, if the worst-case scenario occurs, it will slam into the neighborhood, an interstate highway, and the Yakima River.

Even as emergency managers scramble to move people out of harm’s way, geologists are attempting to observe Rattlesnake Ridge to improve their ability to predict disaster. Landslides occur daily around the world and kill thousands of people each year. Many are fast and furious, occurring without much warning. These are usually triggered by natural disasters: In the months since Hurricane Maria ravaged Puerto Rico more than 50,000 landslides occurred across the island, and the rain hitting California’s scorched landscape this past week caused rivers of mud debris and at least 17 deaths. But other slides, like the one threatening Yakima County residents, play out slowly, creeping along for months before they gain speed unexpectedly.

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