IAS Prelims 2017 Important Topics on Current Affairs: The Union Public Service Commission (UPSC) will conduct the civil services (CS) preliminary examination on June 18 this year. It is one of the most esteemed and toughest exams in the country. With a success rate of 0.1- 0.3 percent of the total percentage of candidates who apply, it is really difficult to nail the examination.
As you know, On 28th March 2017, we have shared IAS Prelims 2017 Important Topics on current affairs which will help you prepare for your upcoming examination. Here is the topic that we have discussed on 31st March 2017, Click on the link below to explore.
As promised, today we are going to continue with the Fifth topic i.e Blizzards. Let us provide you the brief explanation of the said topic.
IAS Prelims 2017 Important Topics on Current Affairs:Blizzards
Current Affairs is an extremely essential component of all major competitive exams. An aspirant who has a grip over General knowledge is always at an advantage, not just for written examinations but also interviews. Updating Daily GK will help you perform well in all the competitive exams.
Let us provide you the explanation of the given topic.
Officially, the National Weather Service defines a blizzard as a storm which contains large amounts of snow OR blowing snow, with winds in excess of 35 mph and visibilities of less than 1/4 mile for an extended period of time (at least 3 hours)
Blizzards are dangerous winter storms that are a combination of blowing snow and wind resulting in very low visibilities. While heavy snowfalls and severe cold often accompany blizzards, they are not required. Sometimes strong winds pick up snow that has already fallen, creating a ground blizzard.
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, or difference in pressure between two locations, which in turn results in very strong winds. These strong winds pick up available snow from the ground, or blow any snow which is falling, creating very low visibilities and the potential for significant drifting of snow.
- A blizzard is defined as a snowstorm in which air temperatures 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. It lasts for a prolonged period of time typically three hours or more.
- It results from interrelationships among snowfall, temperature, wind and patterns of human activity.
- These winds combine with snow and blowing snow to produce extreme conditions.
- The difference between a blizzard and a snowstorm is the strength of the wind, not the amount of snow.
- While severe cold and large amounts of drifting snow may accompany blizzards, they are not required.
- Blizzard conditions of cold temperatures and strong winds can cause wind chill values that can result in hypothermia or frostbite. The wind chill factor is the amount of cooling the human body feels due to the combination of wind and temperature.
Types of Blizzard
Ground blizzards are different from traditional blizzards in that they do not dump any kind of significant snowfall. Instead a ground blizzard occurs when high winds blow snow that has already fallen. There are three main types of ground blizzards: horizontal advection, which has wind blowing horizontally across the Earth’s surface, picking up snow and blowing it; vertical advection, in which there is an upward draft with the wind, blowing the snow high into the atmosphere to create waves hundreds of feet in height; and thermal-mechanical, which is essentially a combination of the previous two. While the latter is rare, it can bury a two-story house and be seen from space.
Lake-effect blizzards, seen most commonly along the shorelines of larger lakes such as the Great Lakes Region of North America, are the products of lake-effect snow combined with high winds. These blizzards are relatively rare due to how lake-effect snow is formed. When cold winter winds blow across the warmer lake water, the winds lift the water vapor into the air and this is dumped along the shoreline. Because lake-effect snow doesn’t often rise when the winds blow too fast, lake-effect blizzards are rare events.
A “traditional” blizzard is, for all intents and purposes, a snowstorm. This means that a blizzard will often include heavy snow and below-freezing temperatures. What makes a blizzard different than a snowstorm is that, unlike snowstorms, a blizzard must have high winds of at least 35mph, or 56 km/h. Additionally, a blizzard must reduce visibility to no more than 1,300 feet for extended periods of time.