Fence next to a \\\'drop off\\\'

[chisum]

My garden level is 3ft higher than a road that runs along the side.(slabs at 45 degrees and concrete retain) I want to put in a 3-4ft fence inside this.
High wind exposure.
Would a 3ft hole and double concrete be strong enough for a larchlap fence? Or would I be better getting shorter panels?

 

[Thermo]

as long as the ground is solid on the retaining side it should be fine with a hole at that depth.