Double black (extreme) Big Sky, MT
Headwaters Hiking Area drops 1,188 vertical feet over feet of skiing, with a steepest pitch of 50°. That's steeper than 98% of the 2,251 double black runs we've measured in North America, and the 3rd steepest of 290 named runs at Big Sky. It faces northeast.
Measured by ZRankings from 1-meter USGS lidar. Steepest pitch is the steepest stretch of about 50 vertical feet along the skiable line. Run lines come from OpenStreetMap and can sit a little off the skied path.