Usually I am over in the shooting and flying forums since that is what I do for a living.
But, I was just involved in another search for a missing snow-machiner who went out on his own and got himself into the ultimate trouble.
All the facts are not in yet, but nobody could raise him on his cell phone and he apparenly could not call out. It looks like he may have gone through some thin ice at an overflow and really dunked himself.
A cell phone that has been under creek or pond water will not help you much even if you are only a mile and a half away from civilization.
But thinking about water proof bags is more of a boating thing than a snow-machine thing.....
I started to think that I am always pulling my phone out of the water proof bag to answer calls from my wife and then stick it right back in a shirt pocket. Since I am usually flying my plane off of lakes, that is also a sure fire way to make sure I can't use it when I need it.
Anyway, just a thought for this yime of year when you guys are running over partially frozen ponds and creeks.