How to restore a replica when all .cvmfs files are gone?

Assuming a large repository, like one from LHC experiments, is there a nice and clean way to fix a broken replica where all the

/srv/cvmfs/<repo>/.cvmfs*

are missing?
Or is the only solution to start from scratch?

A snapshot command should be able to recover from that, although it will take some time because it has to verify all the existing files.