Depending on where you live, winter can bring many different forms of precipitation, including rain, freezing rain, sleet and snow.
So what does it take for different types of precipitation to form? In the winter, precipitation usually starts out as ice or snow crystals at cloud level.
The type of precipitation that falls from the clouds and reaches the Earth's surface depends on the temperature of the air it falls through (a layer of warm air, cold air or both). Learn more about the different types of winter precipitation and how they form.
Rain: Rain forms when growing cloud droplets, ice or snow crystals in clouds collide with each other, become too heavy to stay aloft and fall to the surface as precipitation. The precipitation will eventually pass the freezing level and enter a warmer layer of air, forming rain. When the layer of warmer air continues all the way to the surface, the precipitation will eventually reach the surface as rain.
Freezing Rain: Freezing rain forms when snow first falls into a warm layer of air and melts into rain. As it falls, the rain crosses through a thin layer of cold air very close to the Earth's surface and becomes supercooled before reaching the ground, meaning that the temperature of the rain drops is below freezing without the drops becoming solid. The supercooled rain droplets strike frozen ground and immediately freeze on impact. This creates a thin layer of ice and can cause slippery surfaces that make for hazardous driving, biking and walking conditions.
Sleet: Sleet forms in the same way as freezing rain, with one difference. When the rain crosses into the cold layer of air near the surface, that layer is deeper than the layer that would form freezing rain. The deeper layer of cold air will cause the rain to freeze and form sleet, or ice pellets. This type of precipitation bounces on impact with the ground and can cause slippery surfaces just like freezing rain.
Snow: Snow falls from the clouds and does not pass through a layer of air warm enough to cause it to melt. Therefore, it stays in the form of snow all the way to the ground.
Be prepared for any kind of winter precipitation by making sure your car is equipped with an emergency car kit. And, when trying to clear ice off of roadways, driveways and sidewalks be sure to be smart about salt.