The start is on the D578 between Plan de Baix and Omblèze in the gorges. Pass the Moulin de la Pipe and park just before the Cascade de la Pissoire waterfall, at a place called "Baume Noire".
(S/E) Take the trail that climbs north into the forest (not very visible at the start), which begins a few dozen metres before the waterfall (marked in yellow and green).
(1) At the first crossroads, continue uphill to the left and reach a fork.
(2) Turn right and descend to the canyon at the bottom of the valley.
(3) Ignore the path that climbs to the right and start walking along the canyon, which is quite narrow, between the two cliffs. Two passages are equipped with steps sealed into the rock.
(4) At the exit of the canyon (after about 1 hour), remember to continue for about 20 metres to see the bridge you will need to cross.
(5) After exiting the canyon, turn left and leave the marked trail on your right.
Cross the bridge and continue along a faint path that passes in front of some ruins and follows the meadow on your right to join theGR®®9.
(6) Follow this trail to the left, heading south (do not cross the small stream; if you do, turn back). Climb up through a pretty beech forest and reach the ruins of Le Chaffal (elevation 1,021 metres).
(7) Continue downhill on theGR®®9, join the forest track and follow it for a few metres.
(8) Turn left (elevation 999) towards "Gorges d'Omblèze" / "le Grand Cros".
Follow the well-marked path (yellow and green markings) downhill until you reach the crossroads you passed on the way up.
(2) Continue straight ahead and retrace your steps to the start of the hike (S/E).