What is graupel?

Everything you need to know about “soft hail.”

Winter precipitation is a diverse and not always clear-cut category. You recognize snowflakes when you see them, but what about sleet and hail? Even more confusing is graupel, another form of icy rain that can leave you in a head-scratching mess.

This oddly named, little-known form of precipitation is essentially a mixture of snow and hail. In fact, it is sometimes called soft hail because of their similarities. It is also often described as snowball, tapioca snow, edge snow, and puck.

Learn more about this mysterious weather category you may have seen but probably never heard of.

How is graupel formed?/strong>

Although “Yuanxue” is obviously not as interesting as “Graupel”, it does a good job of describing the process of precipitation formation.

When atmospheric conditions are right, snow crystals may come into contact with supercooled water droplets called frost, a form of frost. The official term “supercooled” refers to a droplet that remains liquid at minus 40 degrees (Fahrenheit or Celsius are the same when the temperature is that low). Only when these icy droplets come into contact with snow crystals do they begin to freeze. The result is a kind of fringe snow crystal.

As the freezing process continues, the original shape and form of the snow crystals are lost in their new frozen properties. This end product is graupel.

Sleet, snow, hail, or graupel?

There is so much precipitation in frozen form that it is hard to know what exactly is falling from the sky in winter. Graupel is most often confused for hail, and while both tend to be spherical, hail is usually larger and always more solid than graupel.

Sleet is also stronger than graupel; it bounces off surfaces when it hits them. Graupel either simply falls to the surface like snow, or breaks up easily when you touch it. They also form differently, with sleet being the result of snow melting and refreezing before it hits the ground.

Graupel does not flake like snow.

grain and avalanche

Grape is very soft and won’t cause property damage like hail, but it can cause bigger problems than a few dents in your car.

Because it is denser and larger than normal snow, graupel can contribute to the formation of slab avalanches. The graupel either acts as a lubricating layer, causing sliding, or becomes a dense lamellar layer, which increases in thickness by 20 to 30 cm.

A slab avalanche occurs when the rock formations beneath dense snow and/or ice become weak and collapse, causing everything above to slide down the mountain. Avalanche suggests that graupel poses this risk because the layers it forms contain “a large amount of void space and poor cohesion.


How is graupel different from hail and sleet?

What makes graupel unique is that Its soft texture. It is smaller than hail and about the size of sleet. Hail is formed from raindrops carried upward by storm air currents into colder parts of the atmosphere, and sleet is formed by the refreezing of partially melted snowflakes, while Graupel is formed when “ultra-cold” water droplets gather and freeze on falling snowflakes.

Why is it called graupe?

The word “graupe” comes from the German “graupe”, which means pearl barley. When these snowballs When it starts to rain, they do look a lot like the round particles they are named for.

Can graupel cause damage?

Graupel is relatively harmless as it is softer than hail. Its only threat is when it falls on easy When an avalanche occurs, it is prone to landslides.