CNN News:冰雨和雨夹雪的形成

Of course, weather plays a part too in Thanksgiving travel. And except for the Pacific Northwest, forecasters are predicting decent Thanksgiving weather for most of the U.S. It should be a welcome relief to travelers in Chicago, Illinois, where hundreds of flights were cancelled over the weekend.

当然了，在感恩节旅行中，天气也很重要。除了太平洋西北地区，天气预报员预测，美国大部分地区感恩节天气良好。这对于芝加哥以及伊利诺斯州的游客来说是一件非常欣慰的事情，因为在上个周末数百个航班取消。

The season`s first big snowstorm arrived. Some parts of the northern U.S. were buried under as much as 20 inches of snow. There were problems for drivers as well, with freezing rain and sleet, making things dangerous on the roads.

原因是首场暴风雪来临了。美国北部部分地区积雪深达20英寸。这对汽车司机而言也是难题，冰雨以及雨夹雪使行驶在路上非常的危险。

SUBTITLE: Freezing rain versus sleet.

标题：冰雨和雨夹雪

It all comes down to the temperature at different levels of the atmosphere.

冰雨和雨夹雪是因为不高度的大气层温度不同而形成的。

Take freezing rain, for example. You start with a snowflake high in the atmosphere. It will enter a warm layer, temperatures above freezing. That will cause the snowflake to melt and basically turn into a raindrop.

例如，冰雨，在高空中是雪花，之后雪花进入温度在0摄氏度以上暖层。这就会引起雪花融化，雪花就会变成雨滴。

That warm layer is so thick that temperatures don`t get below freezing until just above the surface, not enough time for that raindrop to freeze again. So, it freezes on everything it makes contact with, roads, bridges, power lines, tree branches, everything.

暖层温度不低于冰点，并且很厚，融化的雨滴没有时间再次冻结。所以，雨滴就会冻结与所接触的事物，道路、桥梁、电线、树枝等等。

On the other hand, you have sleet, the only difference is that warm layer isn`t so thick and the raindrop has enough time to freeze again. That`s why a lot of times you can hear sleet. It sounds like ice hitting the surface -- roads, cars, anything it touches.

另一方面，雨夹雪是因为暖层厚度较薄，致使雨滴有足够的时间再次冻结。这就是你经常听到雨夹雪声音的原因。它听起来就像冰击打道路、汽车等所接触东西表面。