Late snowfall in the American West is part of the pattern

EVERY DECEMBER residents of Denver, Colorado hang Christmas lights and decorate trees – and sometimes cacti – in their front yards. But this year, the festive image is missing one thing: snow. As of December 8, the Denverites had yet to see snow land on their yellowing lawns, making it the last first snowfall since the records began in 1882. And Colorado’s capital is not alone, because white matter is scarce this year throughout the American West. A new study suggests that future winters may not help much either.

The snow that accumulates in mountain ranges during the winter, called the snowpack, is a natural reservoir. In spring, when it melts, its waters replenish rivers, artificial reservoirs and the soil. The amount of water that arrives in reservoirs each year depends on temperatures, evaporation and runoff, or how much seeps into the soil. But warmer winters in the western states, a consequence of climate change, have resulted in a decrease in the average snowpack. A study published in 2018 found that the region’s annual snowpack has declined by 15-30% since 1915.

The future looks even darker. A new article by researchers at Lawrence Berkeley National Laboratory in California has found that the snowpack in western mountains could decrease by an average of 25% by 2050. The rate varies across the four mountain ranges studied. The Sierras and Cascades could experience a 45% drop in snowpack by mid-century, compared to 20-30% drops for the Rockies and Wasatch / Uinta. So a future without snow seems more imminent in California and the Pacific Northwest than further inland.

The West has already experienced episodes of “snow drought”. But they seem poised to become more common. Researchers suggest that California may experience persistent “little or no snow” by the 2050s, the Rocky States following in the 2070s. Many places are already bracing for a drier future. The California Department of Water Resources recently warned that next year the State Water Project, a storage and distribution system that runs through the center of the state, will initially provide water only for the needs of ” health and security “. Arizona is bracing for cuts to its allotment of the Colorado River, which supplies water to 40 million people in the southwest.

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This article appeared in the United States section of the print edition under the headline “Man Shows Signs of Stopping”

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