Re: “Niño leaves West dry,” May 29
Although it is popular to link as many strange weather phenomena as possible to a few known processes, such as El Niño and La Niña, the extraordinary weather the northwestern hemisphere has been experiencing for well over a year should not be linked to the very recent emergence of the (weak) 2015 El Niño.
The oceanographic and atmospheric research communities have been monitoring and assessing the anomalous conditions in the northeast Pacific and across North America since early 2014. Locally (researchers at University of Victoria, University of Washington and Institute of Ocean Sciences), we have been monitoring the very warm ocean conditions in the Gulf of Alaska, which started to become apparent in late 2013 and peaked in magnitude in early 2014.
The warm conditions (the warm “Blob”) were so extreme that they exceeded four standard deviations over a massive area, a phenomenon that might be expected only once every millennium.
The causes are still being assessed, but a very weak Aleutian low in 2013-14, and a weak polar vortex that allows the jet stream to meander in extraordinary ways have resulted in multi-year droughts in California, heat waves in Alaska, poor ski conditions across the coastal mountains, and two cold winters in the northeast.
A weak El Niño showed up last month, and is only now taking hold in the equatorial Pacific (May 2015). It’s the last crasher to this crazy Blob party, so let’s not give it more credit than it deserves.