Hand Signals for Mountain Snowmobiling

Communication in the mountains can be difficult at the best of times but add to that a running engine, wind, a helmet, snow-covered trees and you suddenly have a near impossible means of advising your buddies that they should avoid the path you chose. So what's the best way to do that? We'd like to learn more about the tricks you use and to get your feedback on Mountain Hand Signals found here: http://sledlink.com/story/december2011/11-mountain-snowmobile-hand-signa...