"Green Gullies" lies on the south face of the Mosterthoek Twins and the route starts in the same Vredehoek valley as the popular walk up to UCT's Waaihoek / Zuurberg property.
The start of the "Green Gullies" route lies on private property and it is necessary to arrange access with the farmer at "Vredehoek".
Southern Africa may not be exactly renowned for its winter alpine climbing, but some interesting opportunities do present themselves to the enthusiast.
The Hex River mountains are the highest range near Cape Town and collect good snowfalls every winter. Temperatures in the shady south facing gullies stay reliably below freezing for long periods of time, and well-consolidated snow is formed. Pure water ice is not really found anywhere, however, and Giants Castle in the Drakensberg has the best possibilities for ice climbing.
In summer "Green Gullies" is known as a scramble that links a series of narrow and steepening gullies on the shady side of the Mosterthoek Twins. After some good winter snowfalls these gullies are transformed from green to white, and the climbing turns into snow mixed with the odd bit of rock. In places the gullies narrow to only a meter or two wide as they weave their way up the mountain.
The angle of the snow is probably 40 to 50 degrees, which is steep enough to go for an unpleasant slide if one were to come off.
Several variations of the standard "Green Gullies" route are possible that increase the difficulty significantly. The insecurity of the ice / snow on the steeper stuff can be quite gripping however!
Altitude gain from the trailhead an up the gullies to the east ridge is about 1050m, another 150m higher up the ridge is the south Mosterthoek Twin at 2031m elevation.
The best descent route is back down the east ridge to the Fouches Nek, and then dropping back into the Vredehoek valley.
Days are short in the Cape winter and an early/alpine start is recommended. The return to the trailhead makes its way through some thickly vegetated slopes in the lower reaches of the Vrededhoek valley, and personal experience has shown that this does do not make for much fun when navigated at night!
In winter conditions:
Crampons and at least 1 walking axe are essential in winter. A pair of technical ice axes is not really required but may be useful at times.
If you're going to rope-up for the climbing, protection is unfortunately fairly sparse and can be found mainly in the rock on the gullies' sides. Snow protection (stakes or flukes) would be of dubious value.
A modest rack of a few wires and 3 or 4 cams should suffice. I've taken hexcentrics #7 and #8 along and found them very useful.
A series of "Green Gullies" pictures from August 2005: