Rebecca wrote an answer about on February 26, 2012

I found this on Canada Goose's website:

LORO PIANA STORM SYSTEM The Loro Piana Storm System® fabric comprises a double barrier:

The Rain System® water repellent treatment for the face of the fabric, where an invisible treatment wraps each fibre so that drops of water bead away from the surface, in addition to protecting the face of the fabric from dust, dirt and liquid stains.
The exclusive hydrophilic membrane laminated on the back of the fabric to create a lightweight, elastic, water repellent, yet perfectly breathable membrane.

This applied membrane layer is without pores and follows the principle of osmosis; taking any moisture created inside the fabric to the outside, while simultaneously prohibiting the entry of humidity.

Hope that helps!