DRAINAGE DITCHES FIGURE 18 Trails that cross fields many times must also cross a drainage ditch that separates sections of a large farm field. In some cases, grooming fills the ditch with snow, eliminating it from concern. But even in those cases, a period of warm weather may cause some of the snow-fill to compact and even melt or the presence of running water may occur, allowing the ditch to reappear. Snowmobilers need to be aware of the presence of a drainage ditch on the trail. The preferred method for signing this condition is to install a Slow sign at a distance before the ditch to allow the snowmobiler opportunity to react to the presence of the ditch with an Object Marker on each side of the trail located in the vicinity of the ditch. This should be done in both directions of the trail. Drainage Ditch 20 Groomed Trail SLOW SLOW SECONDARY