Up here at the Central Library science desk, weather conversations are often much more than small talk. Patrons often want to know how their perceptions match available data, and recently it’s been all about fat raindrops and heavy coats. Has this winter really been unusual? Our research says yes. Seattle has just experienced the coldest winter in 32 years, as explained by Q13. Cliff Mass reports that we received a year’s worth of rain in five months.
So: What happened?
The simple explanation is that we moved from an extended “El Niño” period, typically associated with unusually warm temperatures in the Pacific Northwest, to a “La Niña” period, typically associated with a colder and wetter fall and winter. El Niño and La Niña are part of a natural cycle that the National Oceanic and Atmospheric Administration (NOAA) tells us generally lasts two to seven years. Check out this excellent video from NOAA for a quick primer on how that works.
That said, this year’s manifestation of La Niña appears to be unusual. Seattle may have set records, but overall temperatures were mild. In addition, California got a solid dose of much-needed rain, when a typical La Niña would have brought drought. Curious.
What will come next?
USA Today reports that La Niña has technically ended, and “La Nada” has begun. La Nada is a period characterized by neutral temperatures that is neither El Niño nor La Niña. The National Weather Service suggests that a return of El Niño is possible, but it’s too early to call. Meanwhile, in Peru, an extreme El Niño-like event has led to severe flooding and the deaths of hundreds, but scientists have held off declaring it officially an El Niño.
The Old Farmer’s Almanac, one of the earliest voices to take a position, predicts that spring in Seattle will be warmer and drier than usual, summer will be warmer and wetter, and fall will be cooler and as wet as you’d normally expect. Only time will tell whether this will come to pass, but have a look at their predictions for 2016-2017. Among the predictions we reviewed, they came closer than most.
~ posted by Anne C.