Structure and wind transport of seasonal snow on the Arctic slope of Alaska

Abstract

The winter snow on the Arctic slope of Alaska lasts for nine months each year, yet little is known about it from a scientific point of view. Its quantity has been seriously underestimated (by a factor of three) in the weather service records, and the directions and magnitudes of wind-transported snow were unknown before the studies reported here. Our measurements of snow on the tundra indicate two major types which differ in depth, density, overall structure, and thermal characteristics: the veneer facies, lying on and interacting with the tundra, and the drift facies which forms in certain topographic settings. The flux of windblown snow has been determined by repeated measurements on three carefully selected “drift traps”, such as river banks, which are large enough so they do not fill during the winter. The measurements span 30 years to show year-to-year variability. The largest transport of snow is from the prevailing easterly winds; about half as much is transported by storm winds from the west. The lowest amount is transported by katabatic drainage winds which flow from the south out of the Brooks Range; they extend a variable, and largely unknown, distance northward onto the Arctic slope before they yield to the stronger easterly and westerly winds.