During the cold months, rain and snow are the most common precipitations, mainly in Patagonia.. However, other natural phenomena can occur and disconcert the inhabitants, Among them is graupel, which could fall on the Upper Valley of Neuquén and Río Negro. But what is it?
Rodolfo Merlino, from the National Meteorological Service (SMN), clears up doubts from the Cipolletti station.
“Graupel is what people normally call frost, they are snow granules or granulated snow,” explained the expert who guards the skies of the region. «Frost is more likely than snow in our region. It usually happens annually,” he added.
Asked about the possibilities of the phenomenon becoming present in the region, he anticipated that “for the Alto Valle it can that occurs on Monday night or early Tuesday morning. “If the conditions are met.”
In other regions of the country, the phenomenon has been present in recent days. Even in areas where it is unusual, such as the beaches of the Atlantic coast.
What is graupel? the scientific explanation of the unusual phenomenon
The scientific explanation issued by SMN describes that the temperature of the cloud and the air between the cloud and the ground are what determine which phenomenon we will have. Graupel occurs when the air cools until it reaches negative values, the drop freezes and small soft white ice balls form. From afar it can be confused with snow
If the temperature is always positive, The drop reaches the ground in a liquid state, that is, in the form of rain.
There is a special case in which the raindrop remains in a liquid state, although its temperature is negative. This is known as supercooled water. In this case, the droplet freezes instantly when it hits the ground or objects. And although the phenomenon is rain, a layer of hard ice forms on all surfaces and the ground. This is known as freezing rain.
What happens when temperatures in the cloud are very low? Under certain conditions and with temperatures below zero, The cloud is not composed of liquid water, but of tiny ice crystals that join together to form snowflakes, which will begin their fall toward the ground.
If the temperatures are always negative on the journey, The flake will reach the ground to leave a beautiful white landscape.
If on the way you find With a layer of air that is warmer, the snow melts and turns into rain.
Sometimes it happens that the warmer layer of air is not very large. Then only the smallest flakes will melt, while others can reach the ground. In this case there will be some raindrops and snowflakes at the same time, a phenomenon known as sleet.
