I had the same problem in the spring of 2010. 8, Super Lemon Haze plants. 6 washed away and 2 were drowned. All kinds of mud, debris and erosion so the location itself won't even look the same after a significant flood making finding them pretty tough. Lession learned though, easy watering being close to a creek or river has it's tradeoffs and it's usually catastropic. Good luck.