新视野大学英语视听说教程第四册 Unit 3 Task3: A Blizzard
A blizzard is a sever weather condition characterized by low temperatures and strong winds, greater than 15 miles per hour, bearing a great amount of snow.
Because the factors for classifying winter storms are complex, there are many different definitions of what a blizzard truly is. But it is generally agreed that in order to be classified as a blizzard, as opposed to merely a winter storm, the weather must meet several conditions. The storm must decrease visibility to a quarter of a mile for three hours running. Include snow or ice as precipitation, and have wind speed of at least 32 miles per hour, which means Force 7 or more on the Wind Scale.
Another standard, according to Environment Canada, is that the winter storm must have winds of 40 kilometers per hour or mi=ore, plenty of snow, visibility less than 1 kilometer, a temperature of less than -25 degrees Celsius, and all of these conditions must last for 4 hours or more, before the storm can properly be called a blizzard.
When all these conditions continue after snow has stopped falling, the storm is referred t o as a ground blizzard.
An extensive form of blizzard is a whiteout, when the downdrafts, together with snowfall, become so sever that it is impossible to distinguish the ground from the air. People caught in a whiteout can quickly become disoriented, losing their sense of up and down as well as their sense of direction. Severe blizzard can also occur along with arctic cyclones.
1. What is the passage mainly about?
2. Which of the following is true of a blizzard according to the first standard?
3. Which of the following is true of a blizzard according to the second standard?
4. What is a ground blizzard?
5. Which of the following is in the order of increasing force?
Keys: 1A 2.B3. C 4.D 5.C
For Reference
They can quickly become disoriented, losing their sense of up and down as well as their sense of direction.
