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Most of us know what 3 miles feel like on our local bike path or what it means to gain the elevation of a flight of stairs in our house. But sometimes when reading a trail description, the metrics don’t mean much until we’re hours into a hike, struggling perpetually upward, wondering how these 3 miles could feel so different than those bike path miles.
Need proof? Check out the trails scrolling in the photos here — they are all “bike trails” but look very different! This is a visual representation of why it is important to understand trail ratings.
Thankfully, through guidebooks, online resources, and map reading, it’s possible to be very well informed about what to expect on a given trail and choose a trail that matches your expectations for difficulty. It takes some general knowledge about trail rating systems and trail difficulty factors. Read on for a key to the map or guidebook key, so to speak. You’ll find an explanation of metrics and trail ratings you can use to understand what to expect on a trail and decide if it’s the hike for you.
A great starting point for gauging trail difficulty is the trail class rating system used in the US. This system is an extension of the Yosemite Decimal System used to rate rock climbing route difficulty and includes 5 classes of terrain.
Trail class rating is subjective and can change over time as a trail or route becomes more developed or deteriorates. Often, the best way to get familiar with what the class ratings mean is to hike a few trails. Use the firsthand knowledge gained on the trail to compare to a guidebook. This will help you decipher what a particular guidebook author or website considers each class to be.
Remember that the class rating system simply refers to the difficulty of terrain, not elevation, steepness, or exposure. There is fifth class climbing at sea level, class 1 trail on the summit of some 14ers, and class 2 terrain with significant exposure. The class difficulty rating is helpful for discerning the character of a trail or route, but you’ll need to know additional information to get a complete picture.
Elevation gain (and loss) is a critical metric to know for understanding the difficulty of a hike. Often the description in a guidebook or online includes total elevation gain. To best understand a trail’s vertical profile, study a topographic map of your trail. Note your starting elevation, maximum elevation, minimum elevation, and what happens along the way. Is the trail one long uphill on the way out? Does it maintain roughly the same elevation or undulate along the way?
Consider the grade, or steepness of a trail. An elevation gain of 500 feet per mile is consistent, noticeable uphill; 1000 feet per mile is very steep; more than 1000 feet per mile will have most hikers slowly laboring upward with hands on knees. A good guideline for estimating how steepness will affect hike duration is to budget one additional hour of time for every 1000 feet gained on maintained trail when backpacking and perhaps a bit less for day hiking.
Remember that steep grades are challenging going both up and down. Often, hikers unaccustomed to long or steep downhill hiking will descend no faster than they ascend; downhill is tough on the quads and knees! Also, loose scree and tricky talus slopes can be very slow to descend.
Finally, also consider average and maximum trail elevation. For a hiker not acclimated to high elevation, the effects of altitude can make hiking more difficult as low as 5000 feet above sea level. When hiking at high elevation, budget plenty of extra time, and slow down and listen to your body [link to article about dealing with elevation?].
Yes, these are actual words, not made-up climber/hiker jargon, and they do not all mean the same thing! These terms refer to different sizes of unconsolidated rocks (as opposed to slabs). Scree is the smallest; these rocks range from pinhead to softball size and are perhaps most commonly marble sized. But you don’t have to take measurements to determine if you’re on scree; if an entire slope of unconsolidated material slides out from under you like ball bearings on greased tank armor, then you’re on scree. Traveling across scree is generally characterized by unpleasantness, particularly when the grade is steep. Think loose and slide-prone. In case you’re not yet convinced that you’d like to avoid scree slopes, consider that human travel across scree is almost always very impactful on the environment as every step sends material downhill, disturbing the landscape.
Talus generally refers to large areas of unconsolidated rocks that are larger than scree and smaller than boulders. If you can walk across rocks without them sliding out from under you but the rocks aren’t so big that you’re climbing between them, you’re on talus. Talus fields contain rocks that usually don’t move under you as you cross them (but certainly can), but you can still, for the most part, cross a talus field without making too many climbing moves and with minimal use of your hands. Crossing talus is generally more enjoyable than crossing scree and less involved than crossing a boulder field. Even so, hiking across talus is still much more time consuming than hiking on class 1 trail. Crossing talus usually requires thoughtful consideration of each step.
Boulder fields are just that—large areas of unconsolidated rocks that are roughly Volkswagen sized and larger. Working your way through a true boulder field probably means you’re in class 3 terrain, as scrambling (using your hands) will be required.
While these three terms are not interchangeable, all 3 sizes of material can occur in the same place.
Some commercially available maps rate trails with their own proprietary difficulty trail rating. Often, these ratings systems look like ski/snowboard trail ratings systems: green circle, blue square, black diamond, double black diamond. Usually the map key provides a written description of each difficulty level. These ratings are somewhat helpful, but only in gauging trail difficulty relative to other trails on the map. There is no agreed-upon trail rating system that uses this difficulty scale. Some maps also include written descriptions of popular trails and include notes on trail difficulty in these descriptions.
Commercially available maps also often include trail mileages, indicated by a number printed along a trail that represents the trail mileage between two points, usually represented by small arrows or dots along the trail. If your map does not include mileages, you can estimate it by using the map scale.
When picking the right trail for your adventures, it’s important to consider some factors related to human/environmental interaction. Are you looking for solitude? If so, go somewhere else if the trailhead parking lot is full. If you found a trail on Instagram or in a top ten list, it’s probably crowded. With the tools in this article, you can research out-of-the-way trails and discover new places rather than relying on going where the crowds go. If you do go somewhere crowded, stay on the trail. Don’t further impact the places we love by creating new parking spots, new trail, or wider trail. Implement best practices outlined here [link] for passing others, particularly during COVID-19.
To understand how to decode the map or guidebook and set accurate expectations of a certain trail, let’s take a look at two popular hikes in the American West. First, see the images below, taken from the Sky Terrain Trail Maps Grand Canyon National Park map, 5th edition. First, we see that in this map’s key, the mapmaker provides a scale of difficulty relative to the trails on this map. We also see a key explaining the map’s mileage markers.
The next image is the on-map trail description for the South Kaibab Trail. The pink text near the top of the descriptions tells us that the one-way distance from trailhead to the end of the trail, the Colorado River, is 6.4 miles. For a reasonably fit hiker, that distance could mean a two-hour stroll or an all-day trudge, depending on many factors. Fortunately, we get some very helpful info in the same pink text: the trail descends 4860 feet over those 6.4 miles. Some quick math tells us the trail descends an average of 759 feet per mile, a significant grade. Now we know that the 6.4 mile hike from trailhead to river will be quite steep, and a hiker is likely to feel the toll of the descent just when they have to turn around and hike back up 4860 vertical feet to the trailhead. Knowing that it’s a good guideline to budget one additional hour for every 1000 vertical feet of gain, this hike is starting to look like quite the long outing.
I can also see in the upper right corner of the trail description that the mapmaker rates this trail “moderate” and “difficult” on its proprietary scale. According to the key above, I should expect some “steep, rocky or sustained” grades on the trail.
Finally, the map’s elevation profile gives us additional helpful information. We can see that the trail starts above 7000 feet, an elevation that could prove challenging for those not acclimated to elevation. This chart gives a great overview of what to expect: the descent isn’t punctuated by any uphills of note, and there isn’t much flat terrain. This info is also obtainable by studying the topographic lines on the map, but the chart presents it in an easy-to-understand way.
Next, we’ll take a look at a route description for Mt. Lincoln, a popular 14er in Colorado, provided in Gerry Roach’s book, Colorado’s Fourteeners: From Hikes to Climbs, second edition (1999). Roach offers the following info about the West Ridge route on Mt. Lincoln:
To understand all the info Roach provides, it’s helpful to read the introduction to his book. There he explains the Roman numeral grade system. With only the info we know, however, we can see that he rates this route as class 2, so we can expect some rocky travel that is more involved than a straightforward, maintained trail (see newer editions of Roach’s guidebook for updated trail conditions). We can see that the trail is a 5.4-mile roundtrip, (we know the mileage is roundtrip from reading his introduction). And the trail gains a total of 2600 feet over half that round trip distance, or 2.7 miles. This trail gains nearly 1000 feet per mile, so we know it will be steep. A steep grade and class 2 terrain means this trail will take far longer than a simple 5.4-mile walk in the neighborhood, especially given its maximum elevation of 14,286 feet.
Remember why we adventure. Perhaps on some days, we want only a simple, short walk in the woods to unwind or get some air. But often we seek to challenge ourselves and get to know another corner of our planet. So use all available resources to be sure you’re choosing the right trail for your expectations. Do your research to prevent finding yourself over committed. But once you’ve done your research and have adequately prepared, hike the hike that comes. Prepare as well as possible [ahem, pack the ten essentials, ahem], then be flexible with unexpected challenges. After all, uncertain outcomes are inherent in adventure. And if you’re feeling a bit overwhelmed by all of the variables in planning a trail-venture let us know! We an help you with a simple consultation or a fully customized itinerary!