In winter, the Flume Slide is transformed into a 1500-foot high, open snow-covered face of a semi-alpine nature. In good snow years, it provides an exciting alternative to the regular Flume Slide Trail, adding a distinct mountaineering feel to what is otherwise a pleasant but fairly typical winter hike in the White Mountains. The general angle is on the order of 30-35 degrees, increasing to about 45 in some of the steeper sections around the middle and especially just below the top. The slide has a west-southwest aspect, which means it catches afternoon sunshine (nice on cold winter days), but also giving it significant exposure to the prevailing winds, which is compounded by the absence of trees on most of the slide. Numerous lines are possible, most ending either directly at the summit of Mt. Flume or a very short distance away, along the summit ridge. Conditions can vary from deep powder to hardpack, with everything in between; in addition, the upper part of the slide contains a large amount of loose rock which, combined with snow and/or ice, can be dangerous and should be avoided by staying on snow wherever possible. Avalanche danger is certain to be high after major snow events. In very good snow years, ski descents of the slide are possible, but obviously require expertise in backcountry skiing, as numerous obstacles exist.
To approach the foot of the slide, follow the Flume Slide Trail (see description on the main page) for about 2.5 miles, to the point where the slide is plainly visible in front of you. At some point, the regular trail veers off to the right, following a minor gully. Instead of following the trail, continue along the main drainage, aiming for the large open expanse that is the main portion of the Flume Slide. Once you are on the slide you will know it: the trees rapidly dissipate and the angle increases dramatically once you're several hundred feet above the base.
Near the middle of the slide
As mentioned in the introduction, numerous lines are possible on the slide. The most obvious follows the prominent gully leading to the notch between the main summit and south summit of Mt. Flume. This gully gets quite steep towards the top, and a fall there would send you on a very long ride down. A less exposed but more circuitous option is to angle left, aiming for a line of trees, follow another gully near the trees, and eventually climbing up to a minor ridge that puts you right on the summit of Mt. Flume. If choosing this option, don't get on the ridge too soon, or you will find yourself fighting krummholtz and chest-deep snow drifts the whole way up. Instead, stay in the snow gully until just below the point where it dissociates into nasty-looking bands of broken rock (about 3/4 of the way up), and at that point climb up and left onto the ridge.
Descent is possible either by downclimbing the slide, or via the regular Flume Slide trail or the Franconia Ridge and Liberty Springs trails, passing the summit of Mt. Liberty.
Ice ax and crampons for the slide. Snowshoes and poles may be necessary for the approach and/or the Franconia Ridge.
When to climb
Winter and early spring. In the summer, the slide becomes an unappealing mixture of wet slab, loose rock and krummholtz. The west-southwest exposure of the slide means that it melts out relatively early as the days get longer and the sun higher, so it's unlikely to be in good shape past about mid-April.