I'm right there with you...seeing people running back down would be demoralizing to say the least. My game plan is to do what others suggested: I'll check the weather starting a couple days before (I always get paranoid about weather when I hike the 14ers), dress and pack my Camelback accordingly, and hope for the best. If a storm develops and I haven't yet finished, I'd rather be turned back (but at least be safe) than be stuck in a lightning storm like I was in the Mt. Evans Ascent a couple months ago. So scary...Best of luck in the race, everyone!