BLIZZARDS

BLIZZARDS

A blizzard is a severe snowstorm characterized by strong sustained winds of at least 56 km/h and lasting for a prolonged period of time—typically three hours or more. A blizzard is characterised by air temperatures that are low (generally less than –10 °C) and winds of at least 30 knots (55.6 km/hr) blow falling snow or that, which has already fallen, such that visibility does not exceed 200 m. For a storm to be classified as a strong blizzard,
Winds must blow at a minimum of 40 knots (74: I km/hr),

Temperatures must be no higher than -12 °C and visibility must be effectively nil.
A severe blizzard has winds over 72 km/h, near zero visibility, and temperatures of −12 °C or lower for a duration of at least 3 hours. A ground blizzard is a weather condition where snow is not falling but loose snow on the ground is lifted and blown by strong winds.
The difference between a blizzard and a snowstorm is the strength of the wind, not the amount of snow. To be a blizzard, a snow storm must have sustained winds or frequent gusts that are greater than or equal to 56 km/h with blowing or drifting snow which reduces visibility to 400 meters or a quarter mile or less and must last for a prolonged period of time — typically three hours or more.

Nor’easter blizzards

A nor’easter is a macro-scale storm along the East Coast of the United States and Atlantic Canada; it gets its name from the direction the wind is coming from. The usage of the term in North America comes from the wind associated with many different types of storms some of which can form in the North Atlantic Ocean and some of which form as far south as the Gulf of Mexico.

FORMATION OF BLIZZARDS

There are set of three criteria that must be met for a storm to be considered a blizzard.
First, there needs to be blowing or falling snow that results in a reduction of visibility to less than one-quarter of a mile.
Second, the storm needs to produce sustained winds or frequent wind gusts in excess of 35 mph, and
Finally, the previous two conditions need to continue for at least three hours.
Blizzard conditions often develop due to intense pressure differences. The difference between the lower pressure in the storm and the higher pressure to the creates a tight pressure gradient, which in turn results in very strong winds.
These winds combine with snow and blowing snow to produce extreme conditions. Storm systems powerful enough to cause blizzards usually form when the jet stream (a very fast moving wind, 240-300 km/hr) which in a sense drags cold polar air, dips far to the south, allowing cold air from the north to clash with warm air from the south leading to formation of front (the narrow zone separating cold and warm air masses).
With the colder and drier polar air, atmospheric temperatures fall enough for the development of snow, sleet, or freezing rain.

American Blizzards

When cold, moist air from the Pacific Ocean moves eastward to the Rocky Mountains and the Great Plains, and warmer, moist air moves north from the Gulf of Mexico, all that is needed is a movement of cold polar air moving south to form potential blizzard conditions that may extend from the Texas to the Great Lakes.
Another storm system occurs when a cold core low over the Hudson Bay area in Canada is displaced southward over southeastern Canada, the Great Lakes, and New England. When the rapidly moving cold front collides with warmer air coming north from the Gulf of Mexico, strong surface winds, a lot of cold air advection, and extensive wintry precipitation occur.
Low pressure systems moving out of the Rocky Mountains onto the Great Plains can cause thunderstorms and rain to the south and heavy snows and strong winds to the north. With few trees or other obstructions to reduce wind and blowing, this part of the country is particularly vulnerable to blizzards with very low temperatures and whiteout conditions.
What are its various impacts?

#1. Whiteout

Blizzards can bring whiteout conditions. In a true whiteout there is no visible horizon and multiple reflection allows the sense of direction and distance to be lost. People can become lost in their own front yards, when the door is only 10 feet (3 meters) away, and they would have to feel their way back. Motorists have to stop their cars where they are, as the road is impossible to see. Whiteouts can paralyze regions for days at a time, particularly where snowfall is unusual or rare.

#2. Wind chill

The wind chill factor is the amount of cooling the human body feels due to the combination of wind and temperature. Blizzard conditions of cold temperatures and strong winds can cause wind chill values that can result in hypothermia or frostbite.

#3. Inundation and Flooding

All the snow that blizzards usher in has to go somewhere. When the temperatures start to rise, the snow melts too quickly and abundantly for it to be absorbed, which increases the risk of flooding, especially in coastal areas. Blizzards also cause sea levels to rise, which can lead to flooding. Floods devastate the plant and animal population, shifting the local ecosystem and potentially impacting the food supply. Floods can also spread pollution from oil dropped on parking lots to plastic bags left out on the street; pesticides; fertilizers and detergents. All of these impact the water supply and further poison the plant and animal population.

#4. Destabilised Water Cycle

Whether blizzards result in flooding, they blanket the land with heavy precipitation that is drawn up into the atmosphere as a result of evaporation. Whether it is the snow from the blizzard or the water from the resulting flood, blizzards can contribute to heavy accumulation of water vapour in the atmosphere. That can lead to greater rainfall throughout the rest of the year, including heavy storms. Those storms can raise water levels and impact plant and animal populations, depending on their severity.

#5. Ecosystem impact

Temperatures quickly drop below zero during a blizzard, especially with the wind chill. Ice and winds cause trees to fall and plants to die. Such storms have the potential to cause significant damage to entire forests, which then release carbon during decay. The excess carbon causes an imbalance in the local ecosystem, which impacts other plants and wildlife. When other plants and flora are killed during a blizzard, their lack of availability also impacts the food supply for local animals and wildlife. Additionally,
Trees, plants, and crops can die in a blizzard, because of the extreme cold.
Tree branches and limbs can break.

#6. Mold and Fungus Damage

Blizzards create wet or damp conditions for extended periods, both while there is snow on the ground and while it is melting. The on-going wet and damp conditions encourage the spread of mold and fungi. Some mold and fungi are beneficial for the environment because they help break down decaying matter, like fallen trees. However, some mold and fungi damage the environment by destroying plants and trees that provide food sources and are important to sustaining the local ecosystem.

#7. Effect on city life

1. A blizzard can shut down a city, sometimes for days. Transportation can be impossible. Adults cannot get to work. People can be stuck in their homes for days.
2. Electrical wires often go down because of the heavy wind and snow. This leaves people with no electricity.
3. A blizzard can cause lots of property damage, such as roof cave-ins and windows breaking. Trees can fall on houses, cars, etc.
4. Blizzards are the cause of car accidents. Cars can be stranded on highways too.
5. Blizzards are life-threatening storms taking lives.
6. Blizzards can hurt the economy.