It is a “technical” route, with rope rubs to manage and several deviations, and fairly aquatic. In spring it is usually impassable due to excessive flow caused by snowmelt. The water is also cold because the canyon lies at about 1500 m a.s.l., and the second section is quite enclosed. For this reason, it is recommended to do it in the summer months. The lower section is the most interesting, both in terms of scenery and verticals.

It is a “technical” route, with rope rubs to manage and several deviations, and fairly aquatic. In spring it is usually impassable due to excessive flow caused by snowmelt. The water is also cold because the canyon lies at about 1500 m a.s.l., and the second section is quite enclosed. For this reason, it is recommended to do it in the summer months. The lower section is the most interesting, both in terms of scenery and verticals.

By car: from Varallo, take the Val Mastallone road and follow it to Fobello, then continue to the end of the road near Santa Maria, where you leave it at the last parking lot.

On foot: There are two paths; follow the one on the left, which almost runs alongside the Mastallone stream, passing through a pretty village. Then, cross a bridge over the Mastallone and go up the Piane valley. After a 10-minute climb, you'll find a hut on the right. This is where the lower section begins, on the left of the first large waterfall. Continue past some huts, then the path passes alongside a ravine. When this ends and the valley opens up, descend along tracks in the meadow to the stream (near some huts on the other side). 30 minutes in total.

Re-equipped (18/08/24) and modified some abseils. A single point was added for some difficult downclimbs. However, the abseil with the half-detached belay (the second of the last relay) was left as it was because the high flow rate made it unsafe to equip in such a narrow section. It can, however, be avoided with a C40 outside the gorge. There are two other abseils higher up, but given the distance from the rest of the route, they are less interesting. You enter and find the first C20 (right) (with a hanging pool to overcome), then C18 (right), a little march and you find a small bridge with some large pipes, just after C25 (left) (with rubbing), then MC+C18 (right), here begins a long stretch of walking between large boulders (15 min.) The stream narrows, you find C6 (right) (single point), then C10 (perhaps toboggan, right), toboggan 4m, you arrive at the final, more ravine-like section, MC (left, top, with 3 intermediate points) leads to C30, which ends in a turbulent pool, then C7 (left, single point), C18 (right), C10 (left), MC from tree (right) with subsequent relay C20 (right)+C15 (right), then final C5 (left, single point) and you practically arrive at the starting point in the town near the car park.