From liquid to ice crystals, winter precipitation can vary across the country, and right here in Southern Colorado. It includes everything from snow, sleet, freezing rain and rain.
It all starts as snow, but might not end up that way. As snow leaves the clouds, it will shift between phases of liquid and ice as it encounters pockets of warm and cold air. How storms produce rain versus snow or sleet versus freezing rain all has to do with the layer of air found between the clouds and the ground.
If a layer of warm air is present beneath the clouds, then snow will melt as it moves through this warmer airmass. If there's warm air between the clouds and the ground, melting snow will turn to rain and stay as rain as it reaches the surface.
If the warm layer is thinner, and wedged between two layers of cold air, then what we'll get is either sleet, a mix of rain and snow, or freezing rain.
Freezing rain is the most menacing form of winter weather. It occurs when we see a very thin layer of cold air right above the ground. When freezing rain occurs, rain droplets will re-freeze as they encounter cold surfaces. This includes roads, sidewalks, bridges and power lines.
Ice storms often lead to automobile accidents, power outages and personal injury. Ice will usually collect first on bridges and overpasses, and is especially hazardous to drives since these areas will ice over first.
Because a thin layer of ice can often go undetected, it's important to be prepared when the threat of freezing rain is in the forecast.