OSA ridge

Pretty ridge in excellent rock with good holds, airy, but not sustained.

Approach:
Parking in the hamlet of Belvedere, just above the town of Valmadrera. Small car park.
First follow a concrete road and large stones to a small chapel with a fountain.
Follow signs for Cresta OSA and Samborsera and enter the forest by a broken rocky path. Follow Samborsera.
Then around 715 m altitude, the path splits, to the right in the direction of the south ridge OSA, to the left towards San Tomaso.
Follow the path that climbs through meadows and sparse woods. Ignore a first sign indicating Cresta OSA IV on the left (leading to the first part of the ridge completely covered in grass), climb up 70 m. You then have a nice panorama over the Lecco branch of Lake Como and follow a second sign Cresta OSA III-IV. You arrive at a small flat area where a small spur begins.

Route:
Difficult to go wrong. The ridge is a succession of walls (III-IV) and easier terrain in II.
Towards the middle of the ridge, you reach a chimney (IV), with a jammed block. It is possible to bypass it on the right (III). There is a belay station to the right of the chimney (not quite clear what it is for).
The ridge is easier after the chimney and you reach a saddle after a succession of II-III.
After the saddle, there is one last step (a good IV), but in poorer, crumbly rock.
After this last step, there is an airy section for about 5 m, very playful, not difficult. You then continue towards the summit, there is a large cross and a Madonna.

Time:
Between 1h00 and 2h00 to climb the ridge.

Descent:
From the summit, descend a steep path (partially equipped with chains) leading to a traverse over steep meadows in the westerly direction. You arrive at a fork (characteristic erratic boulder of granite from Val Masino).
From there, path no. 6 with signs for San Tomaso leads to the Sambrosera spring and the car park
(1h, 1h30 depending on path conditions, very muddy in the upper section after recent rains).