UTAH — At 8,164 feet in the Bear River Range in Northern Utah lies Peter Sinks, a limestone sinkhole comprised of two depressions around two miles long and a half-mile wide. Just 20 miles northeast of Logan, Peter Sinks is surrounded by high ridges that trap air and liquid, the perfect environment for cold temperatures. The area holds the record for the second coldest temperature ever measured in the contiguous United States at -69.3 degrees set on February 1, 1985. The coldest temperature recorded was in Montana, and only 0.4 degrees colder.
Peter Sinks’s unique terrain creates a microclimate allowing the depressed area to be different than the surrounding areas. Through cold air pooling, cold, dense air falls from the high ridges to the basin floor while the heat produced throughout the day rises into the atmosphere leaving only cold air. When an arctic front moves into the area, the chance for extreme temperatures increases.
While temperatures have been low across the state, with several areas, including Park City venturing into the negative temperatures during the night, Peter Sinks has seen cold on a different level. From December 15-18, the average minimum temperature was -30.7 degrees, while the average temperature was just over 1.3 degrees. These low temperatures are not the only extremes experienced at Peter Sinks. Rapid temperature changes have been known to occur by as much as 80 degrees in a few hours and 28 degrees within nine minutes.
The Utah Climate Center at Utah State University monitors Peter Sinks. They record the wind speed and temperature in the sinkhole and at the rim of the ridgeline.