If you’ve experienced snow on more than one occasion, you likely noticed that it’s never truly the same. Some snow is sticky and wet, while some is powdery and dry. But wait, isn’t snow created from water? How can it be dry? I understand the confusion, believe me. Snow is a strange thing, never falling in the exact same way. I want to try to explain some major differences in snowfall, though. The most apparent is the difference between wet and dry snow. If you’ve tried to build a snowman with the latter, or perhaps made a too-hard snowball out of the former, this will hopefully clear up some confusion.
Snow can be wet and dense or light and powdery. Surface temperature is the primary cause for these differences. When the surface temperatures are just above freezing, snow can melt slightly, which adds more moisture. The added moisture melts crystals around the edges, allowing them to stick together and become big, heavy flakes. This creates heavy, wet snow, which sticks together easily and is perfect for building snowpeople and other structures.
In contrast, light, powdery snow contains less water. Generally, around five inches of dry snow will melt to be only half an inch of water. The same amount of wet snow will melt to be around an inch of water. Powdery snow is formed when air temperatures are very cold. Dry, cold air will produce small, powdery snowflakes that don’t stick together. These are more likely to drift in windy weather, and they are less likely to cause ice build-up.
Snow is a tricky thing, and it can be difficult to anticipate the types of activities and precautions you may need to take to prepare for a large storm. The best way to anticipate the type of snow is to keep an eye on the temperature when snow is forecasted. When temperatures hang out in the mid-30s, it is likely to be heavy and wet; anything under 32 and the snow will be relatively harmless powder.