The cold temperature in Peter Sinks, Utah

Dear Tom,
On Jan. 1, the low temperature at Peter Sinks, Utah, was -48 degrees, the coldest in the Lower 48 that day. Surrounding temperatures were in the teens. How can Peter Sinks get so cold?
— Bud Dyke
Dear Bud,
Peter Sinks, located in extreme northern Utah, occasionally registers the nation’s coldest temperature on a given day (and on Feb. 1, 1985, its temperature dropped to -69 degrees, only one degree shy of the Lower 48’s all-time low of -70 degrees at Rogers Pass, Mont., on Jan. 20, 1954).
Low temperatures at Peter Sinks are the result of its high elevation (8,164 feet) and unique topography. It is a basin 1 half-mile in diameter with no outlet, like a large bowl. Cold air collects in the basin on clear, calm nights. Very low temperatures can occur there, especially during outbreaks of arctic air in the winter.