Black diamond
From FIS Freestyle wiki

Black diamond, Difficult Amongst the most difficult at a given mountain. Black Diamond trails tend to be steep (typically 40% and up) and may or may not be groomed, though the introduction of winch-cats has made the grooming of steep slopes both possible and more frequent.
[edit] Slope Steepness

There are two ways of measuring slope steepness. The first is a measurement using degrees, which measures the angle of the slope in degrees from the horizontal. The second is a percentage.
This is calculated using the formula 100*rise/run. Rise is the vertical change and run is the horizontal distance. A 100% slope is angled at 45 degrees.
- 10% is equivalent to 5.71º
- 20% is equivalent to 11.31º
- 30% is equivalent to 16.7º
- 40% is equivalent to 21.8º
- 50% is equivalent to 25.67º
- 75% is equivalent to 36.8º
- 100% is equivalent to 45º
A beginner slope is typically between 6% and 25%. Intermediate hills range from 25% to 40%, and expert is 40% plus.
[edit] Also see
- Green circle
- Blue Square
- Black diamond
- Double black diamond
- Skier Rider Ability Level
- Slope
- Grade
- Inclinometer
- Mountain
- Degree
- Average Grade
- Trail System
- Average Grade
- Average Width
- Mountain master planning process
- Maximum Grade
- Ski resort
[edit] Reference
- Wikipedia Ski trail ratings [1]
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