Who sent us this crazy cold weather ...18*F in Austin 
I heard a great thing on NPR the other day........
So back in the day, there was an arctic jetstream of fricken cold air, and it basically circled around the top of the earth. It never came down and mixed with our air due to temperature/moisture gradients caused by the ice. Well, since the arctic ice is melting these gradients are more gradual now, and this allows the arctic jetstream to 'escape', and so large bulges of it break off and now bleed south. At least this was how they explained why we saw a lot more snow and cold temps in the south this year. They say as the gradients become more gradual (aka, as the ice keeps melting) larger and larger pockets will come down and its just going to get more exciting.