I am aware of some German work that suggests the cold outbreak pattern might somehow be stimulated by reduced Arctic Sea Ice. I have not seen the study but count me skeptical.
The cold and snow in Europe was “balanced” by very warm temperatures in Greenland: classical negative NAO [ North Atlantic Oscillation]: perhaps.
The was a large so-called blocking high in North Atlantic that led to the polar outbreaks into Europe and so that is where the cold air went, making it warmer in behind. Now that is more a weather or meteorological description, not a statement of cause.
Coincidentally pressures have been much above normal in the far North Pacific, and that is typical with La Nina. The pressures were high enough to make the main branch of westerlies active to the south and led to the pineapple express and heavy rains in California. It is quite a strong La Nina, and that is a forcing of the atmosphere by the anomalous atmospheric heating patterns linked to SSTs [sea surface temperatures].