The black Tunnel run beneath the Pic Blanc cable is one them, the pitch is of standard black steepness but can be very hard in the mornings due to late afternoon sun, and super-mogully in the afternoons, so it is not for the faint-hearted.
Those skiers who realise that they have bitten off more than they can chew can cut off onto the cat track to get down. Bear in mind that this piste can be subject to quite a few random closures due to condition changes.
Fearless intermediates can enjoy this really long black run from the top of Alpe d'Huez, there are two ways that you can approach this spectacular run:
The Sarenne - as she should be done: Access to the Sarenne is as per the Tunnel run and simply found by passing the tunnel entrance and continuing as far as you can go. You therefore have to cope with the black that precedes the Tunnel which is not as daunting as its grading suggests. The Sarenne run then continues for an arguably 17 kilometres and is not black. The run alternates between blue and affable red until it enters the Sarenne Gorge when it rather fizzles out into a 5k flat path. Where it distinguishes itself is that the scenery is stunning, the run is undoubtedly long and you ski a non-stop vertical descent of nearly 2000 meters feeling that you are skiing in an undeveloped area of mountain (which you are!) The reason that the Sarenne is rated black is partly because there is a wide steep 'nearly' black section at the top but mostly because once a skier has commenced the run, it is not possible to turn back.
The Sarenne - alternative: By taking the Marmotte III lift you can ski a couple chairlift served, very high altitude red and blue runs that liaise at the bottom with the Sarenne run and also miss out the black aspect of the Sarenne. There is no run back from the Marmotte III lift that will return you to Alpe d’Huez other than via the Sarenne.
Elsewhere another cluster black pistes worth a mention include the runs off the Marmottes II gondola from the Clocher de Macle, Balcons a steep and quiet run, Clocher de Macle is slightly easier but often busier and then there is the long Combe Charbonnière which requires a fairly long traverse at the start.