I highly recommend this ski traverse – the descents are long and fall line, the terrain is varied and interesting, views are gorgeous. There are multiple route options and some steep descents are possible from the top of both peaks.
Logistics are a little tricky for this trip and permission to cross West Wanaka Station private land is required from the Cochranes (03 443-7144). Also the lower the snow line the better as it saves on knees for the short but tiring end of day walk into the Matukituki Valley.
Anyhow here is the plan in a nutshell.
a) Get permission from West Wanaka Station
b) Arrange a chopper flight with Aspiring Helicopters. Cost is around $100 per person for a 6 seater.
c) Park a vehicle in West Wanaka Station at the base of the Buchanans (see map). The car needs some clearance for the farm road and fords. A Hi Ace van or Toyota Carib has enough.
d) Either drive back in a second vehicle to Aspiring Helicopter base at bottom of Treble Cone ski field, or, arrange with WW Station and Heli company to pick up from where the car is parked at bottom of Buchanans
e) Fly to top of Mt Alta and ski. There are several options from the summit. On the route we took we skied a lovely 500m pitch to the south of the summit, then traversed on benches over the Buchanan-Alta dividing ridge. We then skied western slopes to a couple of wee lakes at the 1400m contour. From here we angled upwards to regain the ridge which took us to the summit of Buchanan Peak. The top is always pretty rocky and windswept but there are some steep lines from the summit to the SE. Otherwise ski the Western aspect down to around the 1700m contour before skiing the SE aspect. With food snow cover a great ski down to the farm track can be had, before the final walk down to the car.
Have a look at the accompanying map and you might be able to make some sense of my description.