Possible return of El Nino is a puzzle
This is a chart of El Nino patterns. Generally, the phenomenon of warm Pacific water currents happens around once every 10 years.
The El Nino in 2015-2016 follows that pattern.
Where it gets weird is that it hasn't been followed by La Nina, which is the opposite -- a cooling of ocean currents. In previous cases of El Nino, it was followed by years of La Nina. This time, there was only a weak La Nina last year and now it's threatening to swing back to El Nino.
Why? No one knows. But it may make for an especially unusual year of weather.
More at the Weather Network.
