[originaltext] At the end of every year, U.S. weather researchers look back

At the end of every year, U.S. weather researchers look back at what the nation’s weather was like, and what they saw last year was weird. The year was hot and annoyed by all manner of extreme weather events that did a lot of expensive damage.
    December, in fact, was a fitting end.
    "This is the first time in our 121-year period of record that a month has been both the wettest and the warmest month on record," says Jake Crouch, a weather researcher. The rest of the year was very wet and hot too, he says—the second-hottest period on record for the U.S.
    The cause: a warming climate and a super strong El Nino. El Nino is a weather phenomenon out of the ocean that hits every few years and affects weather globally.
    Together, climate and a very strong El Nino pushed the weather in the U.S. as warm as its 20th century average.
    And even when the atmosphere is only that much warmer, it holds more moisture, leading to record snows in the Northeast last February and March, and record rain in the South and Midwest.
5. What was weather in the U.S. like last year?
6. What made last year’s weather so wired?
7. What happened in the Northwest of the U.S. last February and March?