Didn't we just talk about wool's absorbency yesterday? How can wool be both absorbent AND water resistant?
Because wool is awesome. It's the inside of the wool fiber -- the cortex -- that helps make wool absorb moisture. Each fiber also has a layer of tiny, overlapping scales on the outside -- known as the cuticle. These scales help cause water bead up and roll off the surface of a blanket or garment. Wool's natural fats and oils also help repel water... but all this doesn't mean you should make your next wetsuit out of wool. Wool can repel water, but isn't totally waterproof.
So complex... so versatile... so wonderful!