Ok first off, just like any cliff, make a big back, preferably wider than it is taller.



Now, using the front view split it up into boxes with the clip tool. The boxes dont have to be even spacing, randomize it up a little.



After that take each square you have and split it diagonally with the clip tool again. You should see many different triangles. Only split the squares in one direction. (Don't make an X, that doubles r_speeds)



Using the top view and vertex manipulation, pull out different sections so that it resembles the picture below:



Now use front view again and drag the points around in random directions. The end result should come out to be something like this: