from a Gizmodo post, 23xii21

...natural climate pattern known as La Niña favors this exact winter setup. The cooler-than-normal waters in the eastern tropical Pacific alter weather patterns all around the world. That includes making the jet stream take on a more wavy pattern over the U.S., allowing cold air to plunge from the Arctic into the Northwest and heat to come bubbling up from the tropics to the southern and eastern portions of the country. The intensity of the heat is impossible to talk about without mentioning climate change, though. Burning fossil fuels has locked in a legacy of heat that’s only becoming more clear with each passing season. It was only just a few months ago the Tahoe ski resorts now under winter storm warnings were on fire in a bad way.--