From the Forest Service:

Big Santa Anita Canyon (which includes the Chantry Flats Picnic Area) adjacent to Sierra Madre/Arcadia remains temporarily closed until mid- to late-summer.

More work is being done to repair roads and resurface the picnic area parking lot after the Bobcat Fire and subsequent flooding. In addition, volunteers have been working hard on trail repairs. 

It can take three to five-plus years or more for an area to recover from a wildfire, especially with excessive post-fire flooding. When plants’ root systems are burned out, there is little to nothing to hold soil in place until more regrowth.