There is a lot confusion when it comes to the different types of frozen precipitation that we often experience during the winter, especially in the Midwest and New England.
Rain
The most obvious type of precipitation that we usually see on a daily basis is rain. Usually when precipitation falls in the atmosphere it encounters warm air in place on the way down that keeps the precipitation falling as rain as it comes down.
Freezing Rain
Freezing rain is a bit different compared to rain. This starts similar to the last instance in which precipitation high enough in the atmosphere is in the form of ice crystals but on the way down it becomes rain, however when it nears the surface, if the surface temperature happens to drop below freezing as it falls at the surface this can fall on the ground as freezing rain meaning that the rain freezes on contact. This is known as the one of the most dangerous types of precipitation due to its severe impacts on travel.
Sleet
Sleet, similar to the last two with its origin begins as ice crystals as it falls in the upper atmosphere but this time there is only a narrow band of warm air that can accompany it and as it falls through the rest of the atmosphere and towards the surface. Colder air dominates more leading to rain freezing before it hits the surface and falling as ice pellets. Sleet is the safer bet as compared to freezing rain but can still have impacts on travel.
Snow
Snow starts with the similar process as compared to the first three precipitation types we mentioned. However, this time there is no warm air in place meaning that the precipitation that falls through the atmosphere and down the surface with stay as snow due to the fact that there is no warmer air in place to alter the precipitation type. Snow can lead to devastating impacts on the roadways and can wreak havoc on travel, especially with airplanes.
While these may be the main ones that we may experience during the course of the year, there are some types that are not as common but still do occur at any point during the year.
Hail
Hail is much different as compared to the precipitation types that have been mentioned so far. Hail forms when rain droplets get pulled back into thunderstorm clouds due to updraft winds and freeze over. Within the clouds, rain droplets collide with each other over and over again and once the hailstones are heavy enough to not be supported by the thunderstorm clouds, they fall through the atmosphere and onto the surface as hail. This can cause major problems such as damage to any property in the area such as cars, houses, businesses, and much more!
Graupel
Graupel is a precipitation type that is associated with supercooled rain freezing onto a snow crystal as they fall through the atmosphere and hit the ground. They are known to be soft small pellets that often will melt when you pick them up from ground. They can only grow to be less than 0.2 inches in diameter. Luckily, this precipitation type is the most harmless out of all the other types because it doesn’t pose a threat to surfaces or to people.
Sources
https://www.nssl.noaa.gov/education/svrwx101/hail/
