Ahh, lightning’s a different issue. We’ve fortunately haven’t had to deal with big storms while on the river (at least the last 14 that I’ve been involved with). We have had the threat, though, and the instructors typically have their own plans. There are different ways of handling lightning depending on what article you read (some say pull to the shore and stay in your boat, some say get out of your boats and spread out (min 20′ between people). Consistent agreement is not to be paddling in the middle of the river and get near lower-height trees (hoping strikes hit taller trees), avoiding being the tallest abject around.
Good topic and anyone chime in if you have better suggestions or insight!