What is a Blizzard?
The National Weather Service defines a blizzard in the United States as a severe snowstorm characterised by strong winds causing blowing snow and low visibility with low-temperature weather. The difference between a blizzard and a snowstorm is the amount of snow, not the strength of the wind.
A snowstorm can be classified as a blizzard only if it has a frequent gusts of 56 km/h (35 mph) or more, along with the blowing or drifting of snow which can reduce visibility to 400 m or 0.25 mi or less and must last for an extended period of time—typically three hours or more.
Blizzards can be accompanied by severe cold and large amounts of drifting snow, but they are not required. Blizzards can cause whiteout conditions and paralyse areas for days at a time, especially in areas where snowfall is unusual or rare.
A severe blizzard is defined by winds of more than 72 km/h (45 mph), near-zero visibility, and temperatures of 12 °C (10 °F) or lower.
Antarctic Blizzards
While the sky in Antarctica may be clear, a white-out blizzard may occur at ground level due to strong winds whipping up the fallen snow. The wind sculpts the snow into irregularly shaped ridges known as sastrugi, which are difficult to navigate. Blizzards are common on the continent and have hampered the efforts of several exploration teams.
Blizzards in Antarctica are associated with winds gusting over the ice plateau at an average speed of 160 km/h (99 mph). During a blizzard, Antarctica weather includes winds that gust to more than 120mi (193 Km) per hour and are also attributed to being among the strongest winds on Earth.
What is a Ground Blizzard?
A ground blizzard is a weather condition in which strong winds lift and blow loose snow or ice on the ground. The primary difference between a ground blizzard and a regular blizzard is that no precipitation is produced at the time, but rather all precipitation is already present at the surface in the form of snow or ice.
What are Nor'easter Blizzards?
A nor'easter is a large-scale storm that occurs off the coasts of New England and Atlantic Canada. Its name is derived from the direction of the wind. The wind associated with many different types of storms, some of which can form in the North Atlantic Ocean and some of which can form as far south as the Gulf of Mexico, is the source of the term's use in North America. The term is most commonly used along the coasts of New England and Atlantic Canada. This type of storm has hurricane-like characteristics.
Primarily, it refers to a low-pressure area with a centre of rotation just off the coast and leading winds rotating onto land from the northeast in the left forward quadrant. High storm waves have the potential to sink ships at sea, as well as cause coastal flooding and beach erosion.
The Great Blizzard of 1888 is a noteworthy nor'easters, which was one of the worst blizzards in US history. It dumped 100–130 cm (40–50 in) of snow and had sustained winds of more than 45 miles per hour (72 km/h), resulting in 50-foot snowdrifts (15 m). Railroads were shut down, and residents were forced to stay in their homes for up to a week. It killed 400 people, the majority of whom were in New York.
Black Blizzard
During the Dust Bowl, severe dust storms, dubbed "black blizzards," swept across the Great Plains. Some of these transported Great Plains topsoil as far east as Washington, D.C. and New York City, while others dusted ships in the Atlantic Ocean.
Billowing clouds of dust would obscure the sky for days at a time. The dust drifted like snow in many places, and residents had to clear it with shovels. Dust found its way into even the most well-sealed homes, coating food, skin, and furniture.
Some people got "dust pneumonia," which caused chest pain and difficulty breathing. It is unknown how many people died as a result of the condition. Estimates range from hundreds to thousands of people.
On May 11, 1934, a massive dust storm two miles high travelled 2,000 miles to the East Coast, obscuring landmarks such as the Statue of Liberty and the United States Capitol.
On April 14, 1935, the worst dust storm occurred. According to media reports, the event was dubbed "Black Sunday." A wall of sand and dust began in the Oklahoma Panhandle and moved east. During Black Sunday, up to three million tonnes of topsoil are estimated to have blown off the Great Plains.
FAQs on Blizzard
1. What exactly is a blizzard in Geography?
A blizzard is a severe and dangerous snowstorm defined by a specific set of conditions. To be classified as a blizzard, a storm must have strong sustained winds of at least 56 km/h (35 mph), low visibility of less than 0.4 km (a quarter-mile) due to falling or blowing snow, and these conditions must last for an extended period, typically three hours or more.
2. How does a blizzard form?
A blizzard forms when three key weather ingredients come together. First, you need cold air at or below freezing (0°C or 32°F) for snow to form and stick. Second, you need moisture, like the air blowing over a large lake or ocean, to form clouds and precipitation. Finally, you need lift—warm air rising over cold air—to create the unstable conditions for a powerful storm system to develop.
3. What is the main difference between a blizzard and a regular snowstorm?
The main difference is not the amount of snow but the strength of the wind and the lack of visibility. A regular snowstorm might just involve heavy snowfall. A blizzard, however, is characterized by its fierce winds that whip up snow (either falling or already on the ground), creating whiteout conditions where it becomes almost impossible to see.
4. In which parts of the world do blizzards most commonly occur?
Blizzards are most common in high-latitude and polar regions, as well as some temperate zones during winter. They frequently occur in places like the Great Plains of North America (Canada and the United States), Siberia in Russia, the northern regions of Scandinavia, and across the vast, icy landscapes of Antarctica.
5. What makes a blizzard so dangerous for people and infrastructure?
A blizzard's danger comes from a combination of factors. The main risks include:
- Whiteout conditions: Extremely low visibility can lead to serious transportation accidents.
- Extreme cold and wind chill: The combination of low temperatures and high winds dramatically increases the risk of frostbite and hypothermia for anyone caught outdoors.
- Heavy snow accumulation: This can trap people in their homes or cars and cause roofs to collapse under the weight.
- Power outages: Strong winds and heavy, wet snow can bring down power lines, leaving communities without heat.
6. How do blizzards affect daily life and transportation in the areas they hit?
Blizzards can bring entire regions to a complete standstill. They cause widespread disruptions, including major road closures, the grounding of all flights, and the suspension of train services. Daily life is severely impacted as schools and businesses are forced to shut down, and people are often advised to stay indoors for their safety. The aftermath can also be challenging, with communities needing days to clear snow and restore services.
7. Can you provide an example of a historically significant blizzard?
A notable example is the 1972 Iran Blizzard, which is considered the deadliest blizzard in recorded history. This catastrophic event resulted in the deaths of approximately 4,000 people. It dropped up to 26 feet of snow over a week, completely burying dozens of villages and cutting off residents from any outside help.
