I'll get some orientations of these holes so that we can consider how these holes were designed with the prevailing winds (winter) taken into account.
Adam,
I put the 18th into the discussion because it is so unusual and I wanted to be provocative in discussing Flynn. There are a few other holes with ridges as well. I don't embrace everything he did, but I do enjoy studying everything. The finishing hole at Opa Locka is a bit odd to look at on paper. I don't think those man-made ridges were meant to be very high. If we had the construction instructions, usually on the right hand side of the drawing under the yardage, we would know exactly what they were meant to be. This was a very flat site, so the ridges must have been an attempt at some strategic demand. It is just a guess, but they were probably only high enough to influence where the ball would end up. Shaping the flight of the ball was probably key to negotiating those low ridges. It would seem that Flynn was demanding certain shot tests. From the back tee, it required a pretty good drive to clear the ridge, but one that was shaped properly to account for the fairway slope towards the canal as indicated by the flow lines. Perhaps the weaker player would play more into the ridge from the forward tee and have his ball deflected away from the fairway slope and the canal. I'd never seen flow lines on Flynn's drawings before these drawings. For the better players, the second and third ridges were more visual intimidation than anything else. The stronger player would hit over the third ridge, obscuring the landing area, and feed the ball onto the green. It is weird, no doubt. There are some other outstanding holes as well. Such as
Hole 1
Hole 5 The diagonal bunkers would have their top lines raised above surrounding grade so tha the landing area would be obscured. This technique also foreshortens the perceived distance to the green.
Hole 9 A risk/reward par 5 with a perched green. Note the diagonal along the right side of the green. From short left to long right there is a distance differential of 20 yards. Many times, Flynn would manipulate the topline of the bunker to make it appear to be perpendicular to the line of play so the golfer wouldn't perceive the added distance to carry the right side of the bunker to a back right pin. An early example of this is the revision of the 15th green at Merion East.