I have crossed the Colorado in marble canyon on two occasions, and both times the conditions were perfect--mile temps, good sun, zero wind...BUT I wonder at what point wind becomes a nuisance, and at what point it becomes downright dangerous? I realize when floating downriver that canyon winds often seem to be blowing up river and thwarting efforts to gain distance on the river. A friend coming down from Waterholes spent many hours in the boat fighting such winds. But as far as simple crossings, at what point would you consider the winds to be nuisance and at what point do you hang it up and wait for a better day? I am thinking light variable winds, no problem. Ten to 15 miles per hour though probably equal nuisance winds, and more than 15 mph, better off waiting for a different day. Anyone had any experience performing a ferry in such conditions? Any thoughts here?