Certain types can bring large parts of the country to a standstill, with the possibility of eclipses, impassable roads, icy conditions, power outages and landslides.
It is crucial that forecasters do their best to get it right.
There are three basic types of winter precipitation: snow, sleet, and sleet. The type of precipitation you get is all based on the air temperature at different levels of the atmosphere.
Consider the atmosphere as a long column. If the air column is from top to bottom freezing point, it will have snow.
If there is hot air at the top, and below the freezing point to the bottom of the column, it will have snow. This is because the hot air high in the atmosphere will produce a raindrop. If the raindrop falls and the air penetrates below freezing, it will freeze before falling to the surface. Because rain is basically a frozen raindrop, you can hear rainstorm as it falls on the surface.
Finally, if the entire air column is above freezing point right up to the surface, the raindrop will freeze on contact. It is called freezing rain and it is the most dangerous type of precipitation.
“Some of the most catastrophic winter storms are mainly due to freezing rain,” the national weather service said.
Freezing rain freezes on anything it comes in contact with, causing a dangerous ice glare on roads, trees, power lines and your vehicle. The weight of the ice can drop trees and power lines, which can cause power outages during very cold temperatures.
The ice on the roads turns the roads into ice rinks and can cause major traffic accidents and congestion between the countries.
It takes less than a quarter inch of ice to make travel dangerous. Tree limbs begin to break with a quarter to a half ice accumulation. And if more than an inch of ice accumulates, there will be major damage to the tree and extensive power outages.
The importance of being right
Deciding where the rain ends and the snow begins can make all the difference in the place of cooling machines, airplane covers, school cancellations and so much more. It is also very important to know which areas will get rain or icy rain.
The rain-snow line is a term we often hear when a winter storm is forecast. The term simply defines the point at which the rain turns to snow. In mountainous regions it acquires a vertical connotation and is defined by the altitude at which rain turns to snow.
If the rain-snow line is inaccurately predicted, it could mean that a city expects to get all the rain from a storm and eventually get all the snow. It can have devastating consequences if a city does not plan for snow and does not treat the roads, cancel schools or warn its residents.
The same can be true if a city expects it to get all the snow and eventually get rain. They would have wasted countless taxpayers’ money to treat roads and close businesses in preparation, and then nothing happens.
Most people living across the South can remember a ‘snow day’ where no snow fell. Important decisions such as closing the school should be made during the overnight period when the winter rainfall is expected to start during the morning hours. If the temperature is slightly warmer than expected, the winter precipitation falls as rain and you have an estimated forecast.
For example, it’s essential to know the height of the rain-snow line in Colorado to know if some of the mountain passes along Interstate 70 will be able to stay open. In New York, it is important to know whether the rain-snow line will reach the I-95 corridor or stay west.
Why are bridges the first to freeze?
In the winter weather, bridges and transgressions froze first. This is because they have air on all sides, so they cool down faster than surface roads. Surface roads are naturally more isolated because the cold air is just above the surface, while the ground under the road keeps warmer.
Then you have what is called a winter mix. It’s basically a bit of everything. If you are near the rain-snow line, the rain can turn to snow over time and then to snow. Or snow will turn to rain.
Forecasters have the important task of not only determining what type of precipitation will fall, but also determining when one type of winter precipitation will pass to another type.
It is crucial to know what time rain will change to snow. Will it take place before or after the evening shuttle?
It is undoubtedly challenging and not always perfect. But knowing what will fall and when is the key to staying prepared in winter weather.
CNN meteorologist Taylor Ward contributed to this report.