The other day I was driving through New Hampshire’s Crawford Notch, where my eyes are usually drawn to the tall mountains and long, cascading waterfalls on either side of the road. But on this day my gaze shifted toward the snowbanks lining the narrow highway. The sun was shining and the landscape glittered. The sparkle of sunlight on cold white reminded me of childhood trips, when I would look out the backseat window at passing fields and imagine all those tiny glimmers were winter fairies, twirling and skipping through the snow.

Snow sparkle isn’t (as far as science has revealed) attributable to fairies, but to light bouncing off the snow at multiple angles. “When you have a really cold snowfall, you tend to get a bunch of little individual plates,” explained Adam Gill, a weather observer and meteorologist with the Mount Washington Observatory. “It’s like billions of these little tiny reflectors all over the ground. If there’s a bright light source, if you’re at the correct angle, that light source will reflect back at you.” As we move across the landscape, our angle changes, and light flashes from different directions. » Continue Reading.