>>792930kek, I carry the same cover. Clean it out, wash/dry it, and hose it down with waterproof spray every season.
Pencils won't run if it does get wet. Pen/sharpie is nice to have.
The NatGeo maps are printed on a similar paper to the "rite-in-the-rain" stuff.
They're not designed to be used in a deluge, but light snow/rain isn't going to destroy it.
