GPS and navigation apps have become essential tools for anyone who spends time outside. They make it easier to plan routes, track progress, submit observations and stay safe. And yet, while most people rely on these apps in warm, fair weather, they’re just as valuable in the dead of winter—especially if you're traveling through hazardous avalanche terrain.
Truth be told, these apps have evolved into full-on safety tools, offering reliable information that helps you make smart, informed decisions in the backcountry. And sure, avalanches might seem like a distant threat to most of us, but under the right conditions, they can occur on snowy slopes across the country. And every year, they claim lives. Fortunately, mapping apps can help pinpoint the key factors—weather, snowpack and terrain features—that form an avalanche.
Recently, I had the chance to spend more time with GPS mapping app onX Backcountry just outside Salt Lake City. Full disclosure: I use this app alongside other mapping tools to plan safe, efficient ski tours every winter. But this trip gave me a unique opportunity to connect with the onX team and local guides to get a firsthand look at their latest integration, autoATES (Avalanche Terrain Exposure Scale), which adds another layer of safety for winter adventurers.
The OnX Backcountry app features ATES to help you make more informed backcountry decisions.
The Avalanche Terrain Exposure Scale, or ATES, was introduced in Canada in the early 2000s as a risk management tool for both the public and avalanche safety professionals. Simply put, the scale classifies terrain into four categories (simple, challenging, complex, extreme) based on landscape features. For example, simple terrain might feature a low-angled slope and trees that reduce or even eliminate avalanche exposure. Complex terrain, on the other hand, might contain cliffs, crevasses or terrain traps that make it much harder to reduce exposure.
ATES is simple and easy to understand by design, but turning that information into a feature within a navigation app poses a different challenge. That’s where autoATES comes in. Developed by the onX team, this automated system combines data and firsthand observations from avalanche and snow safety experts to assess terrain risks. It uses factors like slope angle, wind patterns and forest density to build models that predict where avalanches might start, and how far they could run. And to make sure the system is as accurate as possible, onX works with local professionals who provide on-the-ground verification to fine-tune the models and ratings over time.
OnX's ATES shading feature helps you identify avalanche exposure
To fully appreciate the new autoATES feature, I sat down with guides to map out a short tour in Little Cottonwood Canyon using onX Backcountry’s desktop application. When you toggle on the ATES layer, the visual transforms, revealing a vibrant, color-coded overview of the terrain. At first glance, the multitude of colors and shades might seem overwhelming, but once you understand the system, it becomes an easy-to-use planning too.
Here's a quick breakdown of the color codes:
- Green: Simple terrain
- Blue: Challenging terrain
- Black: Complex terrain
- Red: Extreme terrain
Using this layer, you can plot a basic route—shown on my map as a dotted blue line—that deliberately avoids the more complex (black) and extreme (red) exposure areas. While the ATES layer isn't the sole source of data for your planning, it's a useful first step in analyzing the terrain to make safe, informed decisions.
After establishing your route, you can switch off the ATES layer and turn on other layers like slope angle and slope aspect to refine your plan. This multi-step approach ensures you’re not relying on a single source of information, but instead building a comprehensive picture of the terrain, snowpack and what you might expect when you get out there. OnX also allows you to download topographic data, so even if you’re without service, the ATES layering, routing and terrain features are available offline.
And although onX’s autoATES feature might seem like a tool for skiers and snowboarders, its benefits extend to the entire spectrum of backcountry users—from snowshoers and snowmobilers to climbers and even those who frequently travel along avalanche corridors.
OnX Backcountry Senior Content Manager Andy Sovick breaks out his phone to survey the terrain.
When it comes to navigating in the backcountry, there are plenty of apps to choose from—CalTopo, Gaia and even Fatmap (RIP) all have (or had) their own perks. But after digging into the nitty gritty details, I was surprised to learn that onX Backcountry is the only major application to feature ATES layering out of the box. No need to hunt for specific files or set up custom layers—it's all ready to go. Oftentimes, that simplicity can spell the difference between using a feature because it’s available and overlooking it because you need to figure it out on your own. And ultimately, it’s a big win for anyone who spends time in the snow.
