拉尼娜现象（西班牙语：La Niña），又稱反圣婴现象，是一种和厄尔尼诺现象相反的现象，因此用西班牙语中与厄尔尼诺（El Niño）相对应的阴性名词拉尼娜（La Niña）来代表，厄尔尼诺是「男孩」的意思（定冠词专指的男孩，意思是幼年的耶稣，即圣婴），而拉尼娜是“圣女”（女孩）的意思。

                   Seattleites brave the snow during the 2012 winter season. (AP)                

If you thought the over-hyped storm this October meant that autumn and winter will be mild — think again. Experts warn La Nina is coming. And that means some significant weather hazards.

“Get ready for these kinds of things, whether it’s wind, flooding or snow,” said Ted Buehner with the National Weather Service. “It’s that time of year.”

October already has exceeded average rainfall

Buehner said the coming seasons will hold “active, hazardous weather.” That means snow, rain, wind, flooding, and landslides. The Northwest is about to experience a La Nina — following the El Nino pattern last autumn and winter. More specifically, it is predicted to be a weak / neutral La Nina, and that particular type has brought severe weather to the region in the past.

“Historically, it tends to give us some pretty active fall and winter seasons,” Buehner said. “I’d say we’ve already seen a bit of that.”

For example, this October far exceeded average rainfall for the month within two weeks. Buehner points to other weak / neutral La Nina’s to make the point. The Snomegedon of 2008 is one such season. The winter of 1997 was another season. Back then, the Puget Sound region had as much as 2 feet of snow dumped on it at once.

The follow-up to the heavy snow is important, too. In both historic cases, heavy rain followed in January causing severe flooding and landslides.

And in case you forgot what La Nina is:

“La Nina is when the sea surface temperatures in the eastern Pacific tropical waters – west of Peru – are cooler than average,” Buehner said. “As a result, we tend to have the Pacific storm track and the jet stream spending a lot more time at our latitude, versus El Nino which is what we had last winter when the waters are warmer than average. As a result, the jet stream spends a lot more time across California.”

La Nina, the mountains and skiing

This could all be good news if you are a skier or a snowboarder.

The mountains are expected to have, at least, average snow pack. But it could be better than that, according to Buehner.

“Typically, in La Nina seasons we tend to have a pretty healthy mountain snow pack,” Buehner said. “Even the outlook at this point indicates, at least, average snow pack.”