h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Does anyone know if there are still places in the US that sell serious greatcoats? By serious I mean the kind that reach low enough and are warm enough that wearing one eliminates the need for long underwear. Failing that can you think of another way of dealing with moving back and forth between very very cold weather and warm buildings without a chance to change more than outerwear?
Thank You

wellies and slippers

Have you looked at military surplus stores?

So far I've only looked in the mall my grandma draged me to but I'll see if there are any surplus stores near by.