January 12, 2012 —
As the first week of January winds to a close, we are finally getting some typical winter cold weather; overnight temperatures dipped below zero degrees in a few spots in the region. The cold was sufficient to freeze over most of the area lakes and some snow squalls moved through the area, a small contribution to this year’s below average snowfall to date.
So what happens when we get the white stuff to ski on (or to slip and slide on and clean off the windshield)? When water cools to its freezing point and solidifies, the hydrogen bond charges of the individual water molecules cause them to arrange themselves in a six-sided crystalline lattice. When a snow or ice crystal begins to form and more water molecules are attracted, the bond charges in the hexagonal lattice help to form facets, where portions of the crystal grow much faster than other sections. The end result in its simplest form could be a six-sided snow flake millions of times bigger than the original crystal.
Snow flakes and ice crystals have a lot of different shapes; environmental factors play a huge factor on whether you will see powder or granular snowfall at the slopes this weekend. One other thing that happens when water forms this crystal lattice is that it causes water to expand slightly (about nine percent by volume) as it solidifies. A well known result of this phenomenon is burst pipes and broken rain gauges that were water filled when the freezing occurred.