Normally, I call these things 'blobs', but today it is a dagger.
The same thing is hitting Europe, but not as cold because it went over the sea.
However, just as cold in the relative sense. My furnace is on with nice Canadian natural gas. Poor Europe has lost the leaky Rusgas. Wouldn't want that methane warming things up, wouldn't we?
ps. there is some great physics here with how a cold air plunge could maintain a dagger shape. Implies strong properties of cohesion.