I've experienced average up canyon winds on the main part of Deso.....but in Gray Canyon, now that's another story. We used to do a lot of weekend trips on Gray Canyon (Nefertiti to Swaseys take-out), and the afternoon winds could get really hellacious. I have a vivid memory of a poor guy in a whitewater canoe clutching the tammies for dear life on one trip. I ferried him across the river between my Cat tubes to the road side of the river and he pulled his boat up to the road to catch a ride to Swaseys. We stopped and killed the duckies we had in the group, and had those folks jump on a raft the rest of the way. That was not a fun day. I do remember a San Juan where our tarp was destroyed by those winds that BackCountry describes.