I have been trying to get these photos by Nola Barnick up for a couple days now, but my internet has been difficult. These were taken recently near Limekiln. These rock knockers are a Cal-Trans climbing crew, lead by John Duffy. Each year, each climber must be recertified by attending a climbing school held up in the Sierras every year.
Today, they are climbing Alder Creek, getting it ready for the delivery of spider excavators and dozers to be helicoptered in sometime this week. Rock Knocker got some photos of the climbers, but said they had a long way to go when he called.
And yes, Kirsty (see comment below) that is a falling rock to which the arrow is pointing. Not for the faint of heart, that’s for sure!