The Lava River Cave north of Flagstaff is closed once again this weekend. Coconino National Forest officials say the closure is needed to finish an improvement project at the Cave. The area will be closed Friday, Saturday and Sunday and reopen on Monday. The improvement work is a part of a larger effort to provide better visitor services to meet the demand at the cave. The project includes parking improvements, vault toilet installation, new trail access and installation of new informational kiosks.