Green, blue and black: How ski areas rate their terrain | SummitDaily.com
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Green, blue and black: How ski areas rate their terrain

Skiers and snowboarders ride the lift on opening day Nov. 30 at Copper Mountain Resort.
Photo by Liz Copan / Studio Copan

It’s one of those things that seems like it’s standardized: green runs are easy, blue runs are intermediate and black runs are hard. One might expect that would mean an easy run would feel pretty similar from one ski area to another. Those with a bit more experience likely have discovered the truth: There is no universal method for designating a run as beginner, intermediate or advanced. It’s essentially up to each individual ski area.

While ski areas use similar signage and terms to rate the difficulty of their runs — easiest/easier, more difficult, most difficult, extreme and freestyle terrain — Adrienne Isaac, director of marketing and communications for the National Ski Areas Association, said the designations are set by each ski area and don’t adhere to any sort of shared standards.

“These difficulty ratings are subjective and relative to the terrain at that particular ski area only,” Isaac wrote in an email. “Difficulty ratings are intended as a guide to assist skiers in choosing the terrain they wish to ski.”



A family-friendly focused resort might be more cautious in designating a slightly steeper slope as a beginner run while a ski area that focuses on more extreme terrain could rate a steep but groomed slope as intermediate.

Isaac said lessons can be helpful for those who want to explore new terrain within their capabilities.



With no national standards for ski run ratings, the ski areas don’t have a clear-cut way for how they determine their runs. According to Breckenridge Ski Resort spokesperson Sara Lococo, several factors are evaluated when determining the difficulty of a run at the resort.

“Our resort’s trail ratings are not based on any one specific factor but rather a variety of things come into play,” Lococo wrote in an email. “Some of those factors include slope angle/pitch, trail width, terrain characteristics, whether or not the trail has snowmaking and if it will be groomed versus ungroomed, as well as the location on the mountain and how you get to and from the trail.

“So for example with the latter, if you have an easier trail leading to a more difficult trail, it is likely that both would be given the more difficult rating.”

A family of skiers heads down a groomed trail at Keystone Resort with more difficult terrain in view on a nearby peak.
Photo by Daniel Milchev / Keystone Resort

Roger Poirier, ski area program manager for the White River National Forest, said that while the U.S. Forest Service has some oversight in ratings, it doesn’t designate the ratings themselves.

“We do not have black-and-white policy on this. It’s a resort decision that we look at when we review master development plans,” Poirier said, adding that ski areas are simply required to have run ratings.

Poirier said the rating of a ski run is often based on slope gradient as well as terrain features. For example, he said an intermediate or blue run might have a steep pitch for part of the run, but the run would likely receive a higher rating if the steep pitch is sustained. One of the few times the Forest Service will step in regarding a rating is if there is a higher than normal number of skier accidents on a specific run.

“If there’s a lot of accidents on a run, we’ll look at a number of things,” Poirier said. “Looking at the trail rating is one way to look at that.”

Ski area landlord

Aside from special instances or initial planning, Poirier said the Forest Service’s role with the ski areas has lessened over time to become more of an oversight role.

“Our role is we’ve always been the landlord, and we’ve always had resorts in there to provide great skiing for the public,” Poirier said. “The resorts are really good at planning and providing a great guest experience.”

The Forest Service is generally hands off when it comes to the ski areas. The areas that are on public land must pay a fee to the Forest Service based on the income they bring in due to their use of public lands. Those same ski areas also must prepare master development plans, which are meant to “identify the existing and desired conditions for the ski area and the proposed improvements on the national forest system lands within the permit boundary,” according to the White River National Forest website.

All four Summit County ski areas fall within the Dillon Ranger District of the White River National Forest and have provided their development plans to the Forest Service — all of which are posted on the White River National Forest website. Breckenridge Ski Resort, Copper Mountain Resort and Keystone Resort cite a table of “general gradients” created by SE Group to “classify the skier difficulty level of the mountain terrain.” The terrain gradients refer to the slope angle of a run. The slope gradient can be a big factor in a ski run’s ability level rating as well as terrain features associated with the varying terrain of each mountain.

Terrain gradients

• Beginner: 8% to 12%

• Novice: up to 25%

• Low intermediate: up to 35%

• Intermediate: up to 45%

• Advanced-intermediate: up to 55%

• Advanced-expert: more than 55%

Source: Breckenridge Ski Resort, Keystone Ski Resort and Copper Mountain Resort master development plans

Breckenridge’s development plan laid out color codes based on their analysis of Peak 6 terrain:

  • White: Slope gradients between zero and 8% (0-5 degrees) are too flat for skiing but ideal for base area accommodations and other support facility development.
  • Green: Slope gradients between 8% and 25% (5-15 degrees) are ideal for beginner to novice skiers and typically can support some types of development.
  • Blue: Slope gradients between 25% and 45% (15-25 degrees) are ideal for intermediate skiers and typically are too steep for development.
  • Black: Slope gradients between 45% and 70% (25-35 degrees) are ideal for expert skiers and pose intermittent avalanche hazards.
  • Red: Slope gradients greater than 70% (40 degrees and over) are gradients too steep for all but the highest level of skiing. Areas of this high slope are typically allocated as expert only and are closely managed by the ski area operator.

When planning terrain, the ski areas also look at market demand for each ability level and the capacity of skiers each level of terrain can safely hold. The Breckenridge plan, which is from 2007 with a 2013 amendment, compares the market demand for each skier ability level with distribution of terrain by ability level and slope gradient. The plan finds that while it is in the best interest for the ski resort to cater to all ability levels, it will want to cater more to the levels that are most in demand, noting that intermediate skiers “comprise the bulk of market demand.”

A-Basin terrain gradients

• Easier: Less than 25%

• More difficult: 25% to 45%

• Most difficult: 45% to 70%

• Expert: Greater than 70%

Source: Arapahoe Basin Ski Area master development plan

The Summit County ski area that stands out from the others in terms of how it lists it mountain design and site inventory is Arapahoe Basin Ski Area. A-Basin uses different slope gradient ranges for its terrain, which the ski area says is due to A-Basin’s clientele.

“A-Basin has a higher percentage of steeper terrain than most ski areas in Colorado. The skiers that it attracts tend, on average, to be of a higher ability level,” the area’s 2012 master development plan reads.

A-Basin’s general range of slope gradients that it used in the planning of the Beavers is significantly higher than the SE Group chart used by the other ski areas.

The other ski areas list a more general skier ability breakdown based on the central Rocky Mountain region when discussing market demand, but A-Basin made its own, noting that the ski area’s skier ability breakdown skews more toward the advanced end of the spectrum.

Behind the scenes

Peter Williams, senior mountain planner at SE Group, explained that the company works on planning and design for ski areas.

“As part of that planning process, we use various criteria for slope gradient to break out the terrain into different categories, but at the end of the day, that doesn’t influence how the ski areas rate their runs,” Williams said.

Williams said that when planning a resort, it’s extremely important to balance the lift capacity with the run capacity so that there are enough ski runs to keep up with the demand the lifts create.

“The ability level is a very important factor that there’s more intermediate skiers than there are beginner or expert skiers, so we want to have more intermediate terrain,” Williams said.

The final piece of the puzzle is mountain progression. The difficulty of each individual area of the resort depends on topography, but resorts tend to work to define areas based on skier ability when planning the mountain.

A snowboarder carves a turn under bluebird skies on opening day at Breckenridge Ski Resort on Nov. 13.
Photo by Liz Copan / Studio Copan

Loryn Roberson, spokesperson for Keystone, explained that Keystone has a progressively difficult front-to-back layout.

“Dercum Mountain is what the guest is going to see first and is a great place for our skiers and snowboarders to start out,” Roberson said.

Roberson added that behind Dercum Mountain is North Peak, which is more of an “intermediate mountain” with a variety of intermediate and advanced terrain. The final lift-accessed peak is the Outback, which Roberson said is the best place for people to go who are looking for a challenge.

According to Lococo, Breckenridge follows a similar layout with the most beginner-friendly areas on the lower parts of Peaks 8 and 9, more intermediate areas on upper Peaks 7 and 9 and advanced areas on Peak 10.

“A lot of our high Alpine is lift-served,” Lococo said. “You can hike beyond that. Peak 6 is a great area for if you’re upper intermediate to get into the high Alpine terrain. It’s pretty rare to have intermediate in high Alpine.”

Editor’s note: This story previously published in the spring 2020 edition of Explore Summit magazine.



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