North American ski trails are rated using a combination of shapes and colors according to their level of difficulty. Ski resorts began using this system back in the 1960s, and since then it's become the standard method for measuring a trail's difficulty. It may look confusing at first, but the color-coded shapes are actually quite easy to learn.
Before we explain the different ski trail ratings, you should know that each resort makes its own ratings. There's no regulatory body or government agency that determines ski trail ratings. This is something that's entirely up to the resort. So, a Green Circle ski trail at one resort might be easier than a Green Circle trail at another resort.
North American Ski Trail Ratings:
Green Circle: The easiest type of ski trail, typically characterized by wide, open plains with minimal slope gradients of 6-25%. There's minimal risk involved with Green Circle trails, making them a popular choice for first-time skiers looking to learn the fundamentals of the sport.
Blue Square: Moderately difficult ski trails with slope gradients of 25-40%. This is the most common rating, accounting for nearly half of all ski trails in North America.
Black Diamond: One of the most difficult types of ski trails. Black Diamond-rated trails feature steep slopes with 40% or higher grades. Unlike Green Circle and Blue Square trails, Black Diamonds are not always groomed, adding another level of danger for inexperienced skiers.
Double Black Diamond: Intended only for expert skiers, Double Black Diamond trails feature extreme slopes with near-vertical drop-offs. In addition, they may possess other hazards such as exposure to wind guests, rocks, trees, and narrow passages.
Triple Black Diamond: Some resorts may use Triple Black Diamond ratings to alert skiers of trails with an exceptional level of difficulty. The Triple Black Diamond is rarely used, however, and doesn't necessarily indicate a higher level of difficulty than the Double Black Diamond.
Multiple Shapes: Some ski resorts may rate their trails using multiple shapes to indicate a more precise level of difficulty. For instance, a trail with two Green Circles would fall somewhere between a Green Circle and Blue Square rating.
Orange Rectangle: The Orange Rectangle with rounded corners is used for terrain parks, including half-pipes, jumps, etc. Typically, it’s used in conjunction with one of the previously mentioned ratings.