I have some surplus Red Cross blankets that I purchased at the local Army/Navy store. They are thicker, heavier, and larger than the ones typically referred to as "Army Blankets". I keep a couple in our vehicles.

Interestingly, I use a lot of "high tech" material products for everything from outerwear, to sleeping bags. However, in a disaster or emergency, I think the bulk and weight of a heavy wool blanket seems to have a comfort effect that is hard to replace with a lightweight synthetic thing. I don't know how to quantify it, but, I know that when you wrap up in one of these, you feel better. Does that make any sense?