It was 55 degrees and sunny Thursday at Sugar Bowl Resort, where the opening day of the 2021 ski season — already delayed because of warm weather — was still listed as “TBD.”

“Winter hasn’t quite arrived in Tahoe yet,” officials wrote in a note about the postponement. “The team will be working nightly and ready to flip the switch when Mother Nature cooperates.”

But the mountain isn’t the only place feeling the pinch from lack of snow. A new study led by researchers at the Lawrence Berkeley National Laboratory found that dwindling snowpack across California and the western United States could shrink dramatically more — or in some cases disappear — before the end of the century.