Winter storms are characterized by snowfall, rain, sleet, and ice etc where temperatures are below freezing point. A winter storm (or snowstorm) is an event in which the dominant varieties of precipitation are forms that only occur at cold temperatures, such as snow or sleet, or a rainstorm where ground temperatures are cold enough to allow ice to form (i.e. freezing rain). The difference between a blizzard and winter storms lies in the presence and strength of winds. Blizzards are massive snow storms with strong winds.
Definition of Blizzard
A winter storm occurs at very cold temperatures and is characterized by variety of precipitations like snow, sleet, freezing rain, and ice formation. These storms occur in temperate continental climates during winter, early spring and late autumn. Cold temperature is a must for a winter storm. A winter storm that is particularly severe and meets some criteria is called a blizzard.
"Blizzard" has different definitions in different countries. The National Weather Service of the United States define blizzard as continuous winds blowing at 35mph, leading to blowing snow causing restricted visibility of ¼ miles and lasting for a minimum of 3 hours. Even though temperature is not taken into consideration here, it is usually below 32 ˚F or 0 ˚C. Environment Canada defines blizzard as a snow storm blowing snow with winds at 25mph, temperature of -25˚C or -15˚F and visibility of less than 500 feet lasting for over 3 hours. The Met Office in UK defines blizzards as medium to heavy snow with winds of 30mph and visibility of 650 feet or less.
From all these definitions it can be inferred that strong winds, heavy snow and restricted visibility are characteristic of a blizzard.
Types of Blizzards and Winter Storms
Traditional blizzards occur with winds blowing falling snow in all directions while blizzards with no snow fall are called as ground blizzards. Ground blizzards have very strong winds which rake up the fallen snow and blow it around. Ground blizzards usually occur in huge flat expanses of land where there is plenty of loose powdery snow that can be blown by high and strong winds.
Winter storms can be snow storms, freezing rain storms or wintry mixes.
- Snow Storms – huge amount of snow fall creating serious snow drifts, snow piles etc leading to disruption to traffic, school transport, and normal life.
- Freezing rain – this is among the most dangerous type of winter storms. There is a presence of a warm air layer over the region but ground temperature is below freezing point and ambient temperature of around 0˚ C. During this condition roads are frozen. Sometimes, plants and infrastructure gets covered by a coat of ice and then the storm is known as ice storm.
- Wintry Mixes – many a time a combination of rain and sleet is the form of precipitation seen during winter storms or snow and rain alternate with temperature ranging between -2˚C and 2˚C.
Impact of Blizzards and Winter Storms
The most common effect of a blizzard is a whiteout. White outs are very common in the Arctic and Antarctic during spring. White outs occur due to a scientific phenomenon of sunlight being reflected in all directions by the snow and ice. Snowflakes, droplets of fog and ice particles suspended in air enhance the effect to such an extent that sense of direction, perception of depth and balance seem to get lost. The sky and land appear to have blended with a white sheet encompassing everything. Blizzards disrupt life and cause loss of lives, lessened productivity due to inability to reach work places, schools closings, airports are closed, delay in delivery of products etc.
Winter storms cause havoc in regions affected. Death due to hypothermia and infections by frost bites are common. Car accidents are on the rise due to slippery roads and there can be power outages for days on end. Communication can be disrupted with damage to telephone lines and even crops are ruined. Flying becomes dangerous with formation of rime and graupel – rime is a collection of cooled cloud or fog droplets that freezes when it makes contact with an object. Hence when ice crystals fall through rime, droplets of ice get attached to cloud droplets forming graupel. Aircrafts are particularly endangered when it passes through a cold cloud since rime can get formed on its wings.
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