“Trace” and “dusting” are used to describe very light amounts of snow. Is there a difference between the two terms, or are they used interchangeably?
— Brian Dunne, Westmont
We posed your question to Chicago weather observers Frank Wachowski and Paul Kubecka, both National Weather Service retirees, who have been measuring Chicago snowfall since the 1950s. They said there are times when the terms are interchangeable, but not always. A trace of snow is an amount too small to measure (less than 0.1 inch) and could be used to describe a very fine dusting of snow. They cautioned that if it snowed all day, but the snow melted as it hit the ground, the snowfall would still be reported as a trace, but with the notation, “trace, melted as it fell,” and the event could not be described as a dusting.