Dust explained

By Rick Thoman
Alaska Climate Specialist
Alaska Center for Climate Assessment and Preparedness
International Arctic Research Center/University of Alaska
Fairbanks

Dust is not new to Nome and is an occasional environmental feature in many parts of Alaska (not so much in the rainforests of Southeast).
Much of this traces back to the Ice Age, when much of Alaska and the Bering Strait region (then the vast “Bering Land Bridge”) was a very dusty region due to low precipitation and frequent strong winds that readily moved vast amounts of soil material, sand and finely ground rock around the landscape.
Today much of that silt is covered by vegetation, though it is regularly exposed along rivers and through modern industrial activities like mining and road construction. The occasionally severe blowing dust that Nome saw the last ten days of October followed frequent rain the first half of the month. The change in the weather pattern to cooler and much lower humidity allowed road surfaces to rapidly dry out as some of the water soaked down into the road bed while the rest was lost through evaporation or sublimation (when ice goes directly to the gas stage without going through the liquid stage).
The result was a lot of unconsolidated silt that was easily and repeatedly stirred up by vehicles driving on gravel roads, e.g. the “rooster tails” behind trucks or, as we saw the afternoon and evening of October 29, very strong winds. About 8 p.m. that evening, Nome airport briefly reported visibility as low as three-quarters of a mile. Automated weather stations don’t report blowing dust (only human observers do that), so there is no way to systematically check, but that could well be the “worst” blowing dust in Nome in many years.