Data Credits : Inverse ENSO, AO Index and NAO Index
Earlier this year, many weather-watchers were theorising that unusual conditions in the Arctic atmospheric pressure patterns could be behind the deeply cold and snowy winter :-
https://www.nasa.gov/topics/earth/features/coldweather-2009.html
https://www.dailykos.com/story/2010/1/6/822520/-Freak-Current-Takes-Gulf-Stream-to-Greenland
https://climatechangepsychology.blogspot.com/2010/01/weakening-of-polar-vortex-in-arctic.html
The anti-science mob just jumped up and down and yelled at it, calling it “global cooling”, but that’s what you’d expect from a one-dimensional crowd trying to “snow job” the truth about Global Warming.
However, it has now been reliably demonstrated that a combination of a moderately strong El Nino and a very low North Atlantic Oscillation (NAO) index locked in cold conditions and higher than usual precipitation leading to general whiteout in medium latitudes :-