A natural climate phenomenon described as "Godzilla" El Niño—unprecedented in strength—could destabilize the polar vortex over the UK this winter, allowing bitterly cold Arctic air to spill southward into Europe. The polar vortex is a band of strong westerly winds circling the North Pole that normally traps cold air in the Arctic, but when weakened or disrupted, it becomes "wavy" and allows dangerous cold to spread south.
The incoming El Niño, characterized by warming sea surface temperatures in the Pacific Ocean, could be one of the worst on record. Research from the US government's NOAA Chemical Sciences Laboratory found that El Niño "tends to promote the breakdown of the polar vortex, especially in late winter." Professor Adam Scaife, head of long-range forecasting at the Met Office, said: "I have never seen an El Niño signal this intense in our forecasts," noting that typical El Niño events raise equatorial Pacific temperatures by 1 to 2 degrees Celsius, while this one is forecast to far exceed recent experience.
Experts warn the conditions would make the UK likely to face extremely cold, windy, and snowy conditions. Weather forecasters predict it is twice as likely that October to December will be wetter than normal, with high winds expected. The El Niño signal is predicted to peak in November or December, with the Met Office warning that through late winter, a weaker stratospheric polar vortex could increase the chance of Sudden Stratospheric Warming events, raising the potential for cold weather.
British Gas has advised households to prepare by gathering at least three days' worth of food and essentials, including medicines, drinking water, non-perishable food, blankets, and to check home insulation, pipes, and vehicle condition. The Met Office has cautioned that while a polar vortex breakdown could happen, it is not certain.