Dear Tom,
Peter Sinks, Utah, and Death Valley, California, are often the coldest and hottest spots in the country, respectively. What unique characteristics give these places their tendencies the attain such record temperatures?

Jennifer Wakins, Dubuque, Iowa

Dear Jennifer,
Peter Sinks, Utah, recorded a low temperature of -69 degrees on February 1, 1985. It is the lowest temperature ever recorded in Utah and the second lowest temperature in the contiguous United States. Death Valley, California, experienced a high temperature of 134 degrees on July 10, 1913. The Death Valley reading also stands as the world’s highest temperature (although that is currently being disputed by some experts. Additionally, a 136 degree reading in Libya in 1922 was later determined to be inaccurate.)

Peter Sinks is a small high-elevation valley in northern Utah. Sitting at an elevation of 8,164 feet, Peter Sinks is a natural limestone sinkhole approximately one-half mile in diameter. It has no valley outlet to drain out cold air that collects at the valley bottom. During calm cloudless nights, this high elevation basin dissipates daytime heat rapidly into the atmosphere. Cold dense air then slides down to the basin floor and truly frigid temperatures can result when arctic air covers the region during the winter.

Death Valley, California, sits 282 feet below sea level at its lowest spot, Badwater Basin, and is the lowest spot in North America. Death Valley is actually a large area that includes mountains rising 11,000 feet, sand dunes, spring-fed oases and winding canyons. The valley is about 250 miles inland from the Pacific Ocean.

The explanation for the heat in Badwater Basin is its low elevation and the much higher mountains that surround it. The mountains block oceanic moisture from reaching the valley and the descent of air from the surrounding mountains to the valley floor makes very high summer temperatures possible.