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According to Christopher Smart at the Salt Lake Tribune (http://www.sltrib.com/sltrib/news/53029513-78/winds-mph-pressure-utah.html.csp):
The east-to-west wind storm was caused by a cold air mass coupled with a high-pressure system in Wyoming and low pressure in southern California and Nevada, said Larry Dunn, meteorologist in charge at the National Weather Service’s Salt Lake City office. The unusual pressure imbalance set up cold winds that were channeled from the high pressure to the low.
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