Dear Tom,
As I looked out at [Sunday’s] snowfall, I noted that most of it melted as soon as it hit the ground. How does weather observer Frank Wachowski measure the snowfall with any accuracy?
— William J Hopkinson, Maywood
Dear William,
Snow depth measurements are based strictly on accumulated snowfall. When falling snow melts upon contact with the ground, snow depth is reported as “trace — melted as it fell” and, if no measurable snow (0.1 inch or more) occurs during the calendar day, a trace of snow enters the record books for that day. Snow accumulation is measured on a designated surface, usually a snow board — a slab of wood, painted white, and placed where snow accumulation is representative of the area. The water content of the snow (and all frozen precipitation) is also measured and recorded.
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Write to: ASK TOM WHY, 2501 Bradley Pl., Chicago, IL 60618 or: asktomwhy@wgntv.com
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