This "meditation on impermanence" is a companion piece to his 2014 film The Invisible Peak that documents the history of the lost West Peak of Mt. Tamalpais. In Mountains Made of Chalk, Mill Valley artist Genna Panzarella paints a 8×10′ mural of Mt. Tamalpais as it was when it was whole, literally inside what used to be the mountaintop.
For the film, Yost used a DJI Inspire 1 drone to capture breath-taking footage of the creation of a 8x10-foot mural of what a restored Mt. Tam would look like. Panzarella created the chalk mural on February 4, timed just prior to the arrival of heavy rain, hence the 8-minute film’s title. The film, sponsored by Italian Street Painting Marin, was created with the support of the Marin Municipal Water District as part of the ongoing project to raise awareness about the need to restore the West Peak of Mt. Tamalpais.
Both Yost and Panzarella will be on hand for the event. Here's more info.