A few years ago, 82-year-old Wilfred "Wilf" Blezard remembered the coldest day recorded in North America's history. Blezard was one of four weathermen stationed at the Snag airport in Yukon territory on Feb. 3, 1947. On that day, the temperature dropped to minus 81 degrees Fahrenheit.
"We had six dogs that stayed outside the barracks," Blezard said over the telephone from his home in Grande Prairie, Alberta. "Their breath created quite a fog above them."
Blezard remembered tossing water into the air and watching it freeze into pellets before hitting the ground, and listening to the magnification of local sounds created by the severe temperature inversion.
"When a plane flew over at 10,000 feet, it sounded like it was in your bedroom," he said.
On that day, Blezard and his coworkers for the Weather Service of Canada filed a notch into the glass casing of an alcohol thermometer because the indicator within fell below the lowest number, 80 below zero. When they later sent the thermometer to Toronto, officials there determined the temperature at Snag had dropped to minus 81.4 degrees -- the lowest official temperature ever recorded in North America.
I once visited Snag in mid-January with Jim Brader, a meteorologist with the National Weather Service in Fairbanks. We found a ghost town. The airfield that provided a home in 1947 to Blezard and three other meteorologists, several aircraft mechanics, and a few radio operators now features one shell of a log-sided building and an airstrip overgrown with balsam poplar trees.
Canadian and American construction crews completed the Snag airstrip in 1942 as part of a mission to create a series of safe landing places and weather stations between Edmonton and Fairbanks. Much of the air traffic at Snag was from American pilots who ferried planes northward as part of the lend/lease program to the Soviet Union.
The Snag airstrip, located about 15 miles east of the border town of Beaver Creek, Yukon, does not look like the coldest place in North America. It sits on a plateau above the White River, 1,925 feet above sea level. Since cold air acts like water and flows downhill, one might expect a lower temperature in a place like Fairbanks, which is about 450 feet above sea level. Despite its relative height, Snag is the all-time cold champion because of the terrain that surrounds it, Brader said.
"Snag is an elevated valley but a relative low spot compared to the surrounding area," he said.
Cold air that forms in the high peaks of the Wrangell and St. Elias mountains drains downhill and into the narrow White River basin, where the Snag airstrip is located. The high mountains also block the flow of warm, moist air from the ocean. That limits the formation of heat-trapping clouds over the White River basin, Brader said.
On Feb. 3, 1947, there probably were colder spots than the Snag airfield, Brader said. One site may have been the Native village of Snag, about three miles north of the airfield at the low junction of Snag Creek and the White River. The village, which was home to about 10 people at the time, did not have an official thermometer.
"There probably were colder spots, but we don't have a lot of observing sites compared to the amount of area we have," Brader said. "As far as sites where observations were done, Snag was the coldest, but, undoubtedly, there were colder sites."
For the record, Alaska's coldest official temperatures on Feb. 3, 1947 reflected the cold dome of air that hung over Snag. Tanacross registered minus 75 degrees that day, Northway was shivering at minus 70 degrees, and Fort Yukon fell to minus 68 degrees one day later.
Since that February morning when the 26-year-old Blezard witnessed the coldest official thermometer reading in North America's written history, Alaska has come awfully close to beating the record. On Jan. 23, 1971, weather observers at Prospect Creek, a pipeline camp 25 miles southeast of Bettles, recorded Alaska's all-time low of minus 80 degrees. On that day, the temperature at Snag was unavailable; Canadians had abandoned the airstrip in 1967.
Ned Rozell is a science writer at the Geophysical Institute, University of Alaska Fairbanks. He can be reached by e-mail at nrozell@gi.alaska.edu. A version of this column first appeared in 2003
NED ROZELL
ALASKA SCIENCE