In winter, meteorologists have an extra variable they must consider when forecasting snow. We call it, “the fluff factor.” When there is a late summer nor’easter, with respect to precipitation, we just have to forecast how much rain there will be. But with a winter storm, it is not just how much moisture, but also, how fluffy will the snow be?
That heavy, wet stuff is chock-full of water, whereas powder can be full of air and really fluffed out.
Now, the “standard ratio” of what 1 inch of rain would convert to, is 10 inches of snow. But when the snow it is really wet (and heavy to lift), that ratio can be only 4 or 5 to 1, though when it is feather-light, the ratio can exceed 30 to 1!
Expressed another way, depending on the atmospheric temperature profile during the storm, the same inch of water can produce 4 inches of snow, or more than 30!
Fluff factor forecasting is certainly an extra challenge in an already challenging endeavor, forecasting the weather.
Forecasting the weather can be thought of as having a river in front of you and a stick in your hand. You throw the stick in the river and then you must determine how far downriver the stick will be the next day, which way it will be pointing, whether part of it will be submerged, and which side of it will be facing upward.
Piece of cake (I like chocolate)!
Ted Shapiro holds the Broadcast Seal of Approval from both the American Meteorological Society and the National Weather Association. An Alexandria, Va. native, he has been Chief Meteorologist at WAGM-TV since 2006. Email him at tshapiro@wagmtv.com.
