Prescribed Burn- Yosemite Valley Units 10, 14, and 17
The National Park Service is proposing to initiate prescribed burns in 2021 in the Yosemite Valley outer Wildland-Urban Interface (WUI) area. The proposed burn would cover an area of approximately 170 acres of the park within three of the Yosemite Valley burn units (YV-10, YV-14, and YV-17) south of the Merced River between El Capitan to the west and Yosemite Village to the east. This project will build on past prescribed fire activities and recent thinning and pile burning work in the area with the goal of reducing fuel loading within the Yosemite Valley outer WUI buffer.
Prescribed fire preparation may include brush clearing and snagging along holding lines and construction of a minimal handline along the rocky drainage in the middle of YV-14. If additional control lines are deemed necessary to facilitate safe burning and to protect resources, they will be reviewed by an interdisciplinary team and approved by the deciding official prior to implementation. The interdisciplinary team is made up of NPS fire staff as well as cultural and natural resources staff (including archaeologists, historians, and cultural anthropologists/tribal liaisons). Firing operations will be conducted along the holding lines using a drip torch. Helicopters or Unmanned Aerial Vehicles (UAVs) may be used to assist with igniting the burn if needed. Mop-ups of hotspots along holding lines will be accomplished through the use of water and hand tools.
The project is located in the lower Yosemite Valley area, between the El Capitan Crossover Road and the Sentinel Beach Picnic Area. The western holding line will be the El Capitan Crossover Road, between Southside Drive and Northside Drive. The burn will be held on the east in YV-17 at the Sentinel Beach Picnic area where the loop road and parking meet the sandy shore of the river. The northern holding line for all three segments will be the Merced River and the southern holding line will be Southside Drive. There are three points between the western and eastern holding lines where fire can be held if needed. These are the Cathedral Beach Picnic Area access road in YV-10, a rocky drainage running between the river and Southside Drive in the middle of YV-14, and a narrow section at the eastern side of YV-14 where the road is only approximately 30 feet from the river. The rocky drainage and narrow section in YV-14 will likely hold with a minor scratch line or hose lay and should not require significant ground disturbance.
All three units have a long history of prescribed fire, with the entirety of each unit being burned at least once since 1976. The entirety of unit YV-10 has been burned two times (1978 and 1986). The central portion was burned in 1996 and the western section was burned in 2003. The entirety of YV-14 has been burned twice (1978 and 2007). Additionally, the western portion was burned in 1979 and the eastern portion was burned in 1980 and 1990. The entirety of YV-17 burned in 1976. The southern half and a small section in the northern half of YV-17 burned in 1991 and the southern half was burned more recently in 2004.