If you plan to use the WiFi strictly as a P2P transmission medium it is not impossible and I've seen a similar implementations in 3G networks where it is impossible to lay a physical transmission medium to the site.

The biggest problem you will definitely face is when it starts raining, be sure your equipment is kept dry, best to place in an enclosure with just the antenna sticking out, seal the connecting points with insulation as well.

And be sure during configuration you reserve static IP for each point or you'll have problems when the dynamic IP is renewed. Force DL to use 16QAM to help boost your range.