Lemming or Pied Piper?

Strange things going on in the snail world tonight. While prowling in the smirry rain tonight I noticed several snails. Not unusual after rain following a dry spell, but there were so many of them and they were all heading for the raised bed. A raised bed in dire need of TLC - the large clump of pink phlox still bearing last year's tall dried stems. There were at least 20 snails ascending the dry sticks, large mature and teensy weeny baby ones. Why? No tasty reward at the top of the climb, a big clump of hostas further up the garden.

Has anyone else seen this phenomenon before? Any idea why?