Western Tent Caterpillars

Thanks Mandy! Not sure if these are Western Tent Caterpillars or Forest Tent Caterpillars, but Western are more abundant, especially in this ecosystem, so that's what I am going with! :)

Maybe Malacosoma californicum (Western Tent Caterpillar)?
You can move it from the "Other" category to "Arthropods."

Hmmm, considering your location, might not be the "eastern" variety. Probably same genus, though, or at least same family.