Walk five minutes east of the ksar and the modern town runs out into dunes — proper Saharan dunes, soft and steep, rolling away towards the horizon as far as you can see. Erg Warane is the local name for the field; it is part of the much larger Erg Ouarane that stretches deep into the interior. The best time to come is the last hour before sunset, when the dunes turn deep orange and the temperatures drop into something bearable.
You can walk in and climb to the top of the nearest crests in half an hour, or arrange a camel trip with one of the town's auberges for a few hours, a night, or a multi-day journey to Ouadane. The sand is fine enough that you do not really need a guide for the short walk — just take water, a hat, and orient yourself by the line of palms along the wadi before you go.