Warming Causes More Extreme Rain, Not Snow, Over Mountains. Scientists Say That’s a Problem

warming world is transforming some major snowfalls into extreme rain over mountains instead, somehow worsening both dangerous flooding like the type that devastated Pakistan last year as well as long-term water shortages, a new study found.

Using rain and snow measurements since 1950 and computer simulations for future climate, scientists calculated that for every degree Fahrenheit the world warms, extreme rainfall at higher elevation increases by 8.3% (15% for every degree Celsius), according to a study in Wednesday’s journal Nature.

Heavy rain in mountains causes a lot more problems than big snow, including flooding, landslides and erosion, scientists said. And the rain isn’t conveniently stored away like snowpack that can recharge reservoirs in spring and summer.

These Maps Tell the Story of Two Americas: One Parched, One Soaked

In New York City, a tropical storm delivered record-breaking rains this weekend. Heavy downpours caused devastating flash floods in central Tennessee, tearing apart houses and killing more than 20 people. Yet, California and much of the West remained in the deepest drought in at least two decades, the product of a long-term precipitation shortfall and temperatures that are much hotter than usual.

This divide, a wetter East and a drier West, reflects a broader pattern observed in the United States in recent decades.