The trails that lace New Hampshire’s White Mountains have always been steep, rocky, and unforgiving, and that reputation is not an accident. As the New Hampshire Bulletin reports, the crews who charted these routes in the 1920s and 1930s designed them to maximize adventure and challenge, often using lengths of string to mark a straight line up a slope. The result was a network of iconic, direct ascents up the region’s famous peaks. It was also, it turns out, a network almost perfectly aligned with the path that rainwater takes when it runs downhill.
That design choice, made a century ago, has collided with a modern reality: rain events in New Hampshire are growing more intense, and the number of boots on the ground keeps climbing. Together, those forces are reshaping the White Mountains trail experience in ways that hikers are starting to notice, and that trail crews are racing to manage.
A century-old design meets a changing climate
“When the trails in New Hampshire were laid out, they were laid out to maximize adventure, challenge,” Matt Moore, senior operations manager for Appalachian Mountain Club Trails, told the Bulletin. Because so many White Mountain trails follow the fall line straight up a slope rather than easing the grade with switchbacks, they double as channels for runoff. Water that lands uphill funnels directly down the footpath, picking up speed and stripping away soil as it goes.
New England trails were already unusually prone to erosion for this reason. Climate change is now pouring fuel on the fire. As Moore put it, “Climate change is intensifying and accelerating a problem that we already had.” Heavier, more frequent downpours mean more water moving faster down trails that were never built to shed it.
The problem feeds on itself. Soil compaction from hikers’ feet lowers the grade of the trail bed, which lets water accelerate further. Severe erosion can carve massive ditches that are both difficult to traverse and unpleasant to look at. The damage does not stop at the trail edge, either. Compacted soil can choke tree roots and kill the trees lining a path, and sediment washed off the trail can end up in mountain streams, degrading water quality far from where the erosion began.
Record crowds add to the strain
If climate is one half of the equation, sheer popularity is the other. On a peak day, as many as 1,000 people may hike the Franconia Ridge, a level of traffic Moore described as “the kind of usage that I’m sure the original builders never could have envisioned.” A century ago, he noted, visitors arrived by horse-drawn carriage. Today they pour into the mountains on Interstate 93 and other major roads, and every footstep compacts the trail surface a little more.
That surge in visitation is a recurring theme across the White Mountains. The same crowds that strain the trail network also raise the stakes for safety and wildlife management. New Hampshire has leaned on programs like the Hike Safe card and ongoing rescue operations to respond, including the recent hypothermia rescue of hikers on Mount Lafayette. Heavy use has also forced periodic access changes, such as the Lincoln Woods trail closure in the White Mountain National Forest. Erosion is the slower-moving cousin of those headline-grabbing events, but it is no less consequential for the long-term health of the trail system.
The expensive fix: rerouting and hardening
So how are crews responding? For the worst cases, the most permanent and effective solution is to reroute the trail entirely. Trading a steep grade for additional length, often by adding switchbacks, decouples the footpath from the path of runoff and dramatically reduces erosion over time.
Rerouting is not popular with everyone. “People have mixed feelings about it,” Moore said. “People say, ‘I liked the challenge of the old trail.’” But he stressed that the trails chosen for relocation are the worst-case scenarios, places where deep ditches and compacted soil have turned the area around the footpath into what he called a “devastated area” where wilderness once stood.
The catch is cost. Relocation projects are expensive and time-consuming, which means they cannot be applied everywhere they might help. “Relocating to sustainable grades would offer us a more sustainable solution,” Moore said, “but obviously we’re not going to be able to relocate these thousands of miles of trails to sustainable grades.” When relocation is not feasible, crews may instead “harden” a trail by building stone staircases, an equally labor-intensive approach that has to be reserved for the most damaged routes.
Recent major projects illustrate the scale of the work. Crews have hardened the Old Bridle Path on Mount Lafayette by constructing staircases, and they are in the middle of relocating the Falling Waters Trail to fight erosion. That trail remains closed, and Moore said its relocation, a significant undertaking, is expected to be finished “in the next few years.”
The quiet bet: water bars and an army of volunteers
For the vast majority of the network, though, the strategy is far more modest, and it relies on a structure most hikers walk over without a second thought: the water bar. A water bar is a ridge built across a trail, often from a log or a line of stones, designed to divert runoff off the path before it can gain destructive momentum. By interrupting the flow of water, these simple barriers reduce erosion and catch sediment.
What makes water bars work is maintenance, and that is where volunteers come in. Crews and volunteers clean the sediment that builds up behind each water bar and shovel it back onto the trail. Last year alone, Appalachian Mountain Club volunteers cleaned and maintained roughly 5,000 water bars on club-maintained trails. Moore was blunt about how central this unglamorous work will be: “The maintenance of these water bars, that is the primary solution for the next 30 to 50 years.”
Over that span, professional crews will keep targeting the trails hit hardest by climate change for bigger projects, while the steady work on water bars holds the line everywhere else. The erosion challenge is part of a broader pattern of climate pressure on New Hampshire’s outdoors, from longer and more intense storms to shifting seasons that are already lengthening the state’s pollen and allergy season.
Moore framed the choice facing the region in stark terms. Some hikers may resist the idea of altered routes, but he argued that this is precisely the work that will keep Northeast trails walkable for the long haul. As he put it, if people do not change the routes, the climate eventually will.
