Avalanche! - The effect of several tons of snow sliding onto our front deck

After completely dismantling our deck during summer of 2007 in order to replace the rotten sill behind the ledger board, we had a new and slightly larger deck built in its place. That construction was done during the summer of 2008. The Adirondack region experienced a very snowy 2008-2009 winter, and several feet of snow accumulated on our roof. At some point during the thaws of late February/early March, the entire mass - no doubt tremendously wet and heavy - slid off onto our new deck. The result can be seen below.

One big pile of snow

[right] Amazingly the floor of the deck, the pressure treated piers, and the ledger all held up under what must have been a huge impact. It is a testament to the quality work of Peter Ferris & Son of Old Forge who did the construction in 2008.

These images were sent by Jim Huss, our neighbor across the lake, who discovered the damage during an early spring reconnaissance.

[left] The entire front railing came off as a single unit. The posts had been attached to the rim joint of the deck with 3/8" lag screws, which just popped out under the impact. In a sense it is fortunate that the railing unit wasn't attached with bolts to the main deck, which might have lead to much more severe damage.

[right] During the summer of 2009, the deck railing was reattached in conjunction with some other construction work. At the end of the 2009 season, I removed all the vertical slats on the front rail. I am sure that these acted as a "fence" during the prior winter's avalanche, trapping the snow as it came off the roof. I also braced up the front rail with a 2x6 attached to a stump immediately off the front edge of the deck. Hopefully, if there is a similar slide this winter, the mass of snow can just blast off the front deck through the big openings where the vertical slats normally would be.

Next summer I plan to reattach the slats to a light frame instead of directly to the railing, and then bolt the frame to the railing. This will allow me to remove an entire "window" of slats at once after undoing a few bolts, rather than tediously unscrewing two screws on each of 60-odd slats.

If this year's plan of removing the slats and providing additional bracing fails, I will devise some means to hinge the front rail so I can let it down for the winter.