North Cascades National Park has a condition type that shows ...natural (historical) range of variability of vegetation characteristics; fuel composition; fire frequency, severity and pattern; and other associated disturbances.: This condition type, in keeping with the wilderness designation applied to most of the park, equates to a natural let it burn policy overall, so long as people and historical property are not threatened and the fire was lightning-caused. As part of the management plan, the few historic structures in the FMU are prioritized for fire protection including backcountry shelters like Beaver Pass Shelter, and fire lookouts such as Sourdough, Desolation and Copper lookout, all of which are on the National Register of Historic Places.: