SEQUIM, Wash.—The Olympic Mountains that tower above this farming community normally rank among the snowiest places in the U.S., with drifts several feet deep lingering into June.

But this year, the Olympics recorded virtually no snow in all but the highest peaks. The May 1 reading of zero snowpack in the rugged range northwest of Seattle was the lowest since records there began in 1948, and came as statewide snow accumulations totaled a paltry 16% of normal.

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