Ryan's Weather Disasters-Blizzards

*Following Information From: Weather.com

Blizzards
Blizzards are characterized by low temperatures (usually below 20°F) and accompanied by winds that are at least 35 mph or greater, there must also be sufficient falling and/or blowing snow in the air that will frequently reduce visibility to 1/4 mile or less for a duration of at least 3 hours.

A severe blizzard is considered to have temperatures near or below 10°F, winds exceeding 45 mph, and visibility reduced by snow to near zero.

Blizzard conditions often develop on the northwest side of an intense storm system The difference between the lower pressure in the storm and the higher pressure to the west 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 dips far to the south, allowing cold air from the north to clash with warm air from the south.

With the colder and drier polar air comes atmospheric temperatures cold enough for the development of snow, sleet, or freezing rain.

The Dakotas and parts of Minnesota were pounded by a succession of blizzards in the winter of 1996-1997. With few trees or other obstructions to reduce wind and blowing snow, this part of the country is particularly vulnerable to blizzards.

A continuation of the broad central plains that run from the Gulf of Mexico into Canada, this area often experiences severe blizzard conditions, with wind chills of 40°F below or more and whiteout conditions.

Another scenario occurs when a cold core low over the Hudson Bay area is displaced southward over southeastern Canada, the Great Lakes, and New England. As rapidly moving short waves, or areas of upward vertical motion and energy, move around the low, they collide with warmer air coming north from the Gulf of Mexico. This produces strong surface winds, lots of cold air advection, and extensive wintry precipitation.

In the southern central Great Plains, rapidly intensifying low pressure systems moving out of the Rocky Mountains can cause heavy snows and strong winds to the north, while to the south and east are thunderstorms and rain.

When cold, moist air from the Pacific Ocean makes it over the Rockies and into the Plains and warmer, moist air moves north from the Gulf of Mexico, all that is needed is a cold closed low aloft and a strong polar jet for potential blizzard conditions that may extend from the panhandle of Texas to the Great Lakes.

-----------------------------------------------------------------------------------------------------------------------

Following Information From: Blizzard Attack: Winter Storm

Blizzards: The Worst Winter Storms 
A blizzard is a storm which contains heavy snowfall, strong winds, and cold temperatures.  The combination of these elements creates blinding snow with near zero visibility, deep drifts, and life-threatening wind chill values.  

Persons should never venture out in blizzards, nor should they continue to travel if a storm is upgraded to a blizzard.  You should seek shelter, any safe shelter, immediately.  A safe shelter is a public place such as a motel or restaurant if you are on the road, or your home, school, or business if you are already there.  

In a blizzard, winds are 35 mph or greater and visibility is reduced to less than 1/4 mile by falling snow and blowing snow.