Ground blizzard facts for kids
A ground blizzard is a special kind of weather event. It happens when strong winds pick up loose snow or ice that's already on the ground. This can occur even if no new snow is falling, and sometimes the sky can even be clear!
This is different from a regular blizzard, where heavy snow is falling from the sky. Ground blizzards can be quite dangerous because they often happen after a winter storm has passed. People might think the bad weather is over, but then strong winds kick up the old snow, making it hard to see and travel.
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What Makes a Ground Blizzard?
For a weather event to be called a ground blizzard, it needs to meet certain conditions. Weather experts in different countries have specific rules for this.
- In the United States, the National Weather Service says a ground blizzard has winds blowing at 35 miles per hour (about 56 km/h) or faster. Also, you can see less than a quarter of a mile (about 400 meters) because of the blowing snow. These conditions must last for at least 3 hours.
- In Canada, Environment Canada says winds must be 40 km/h (about 25 mph) or more. Visibility must be less than 400 meters (about a quarter-mile) due to snow or blowing snow. These conditions need to last for at least 4 hours.
Types of Ground Blizzards
There are three main ways ground blizzards can form:
Horizontal Wind Blizzards
- This is the most common type. The wind blows mostly flat across the ground. It picks up snow and carries it along the surface. There isn't much air moving upwards.
Vertical Wind Blizzards
- In this type, the wind not only blows across the ground but also moves strongly upwards. This lifts the snow high into the air, creating huge, drifting waves of snow. These snow waves can reach heights of up to 500 meters (about 1,640 feet)!
Mixing Wind Blizzards
- This is the most extreme type. Large, swirling air currents, called "convective rolls," form in the atmosphere. These rolls can lift snow so high that the blizzard might even be seen from space! The snow forms patterns that look like waves on a lake or ocean. These conditions are very dangerous and can make it almost impossible to breathe if you are caught outside.
Where Do Ground Blizzards Happen?
Ground blizzards can happen all over the world. However, the shape of the land, called topography, plays a big role in where they form.
- They need large, open, and mostly flat areas. If there are many trees, especially evergreen trees, they can catch the drifting snow and reduce the blizzard's effects.
- The temperature must also be cold enough so that the snow on the ground doesn't melt. If it melts, the ice crystals stick together, making it harder for the wind to pick them up.
Ground blizzards are common in places like the American Great Plains and the Canadian Prairies. They often happen after snowstorms that leave light, dry snow, which is easy for strong winds to lift. You can also find them in Siberia and Northern China. In the Arctic and Antarctic regions, they are common during the spring and fall seasons.
Famous Ground Blizzards
- The Blizzard of 1977 affected Western New York and Southern Ontario. It was a famous example of a ground blizzard.
