Flatirons Climb 5.5 from Gerry Roach 'Flatiron Classics'Climbs the entire arete of Ridge 4 in Skunk Canyon Flatirons, Boulder Colorado. This route is OK. It has a few hard sections seperated by loads of Class 4- 5.easy terraign. A good classic climb for a first time Fatiron lead. A few cleavages in the formation contribute to some strange routefinding and unusual moves.