Visitors must walk across the wide and shallow Medano Creek to reach the dunes in spring and summer months. The creek typically has a peak flow from late May to early June in most years. From July through April, the creek is usually no more than a few inches deep, if there is any water at all. Hiking is permitted throughout the dunes with the warning that the sand surface temperature may reach 150 °F (66 °C) in summer. Sandboarding and sandsledding are popular activities, both done on specially designed equipment which can be rented just outside the park entrance or in Alamosa. Visitors with street-legal four-wheel drive vehicles may continue past the end of the park's main road to Medano Pass on 22 miles (35 km) of unpaved road, crossing the stream bed of Medano Creek nine times and traversing 4 miles (6. 4 km) of deep sand. Hunting is permitted in the preserve during the months of autumn, while hunting is prohibited within national park boundaries at all times. The preserve encompasses nearly all of the mountainous areas north and east of the dunefield, up to the ridgeline of the Sangre de Cristos.