I have seen that kind a lot in Thiruchendur.. I remember this very because, I used to wait for that long big wave to come, but, alas, it used to go white and foamy much before it reached the shore.. and again I wait for the next big one... like that.. so, does this happen only when the bottom of the wave slows down than the top of the wave? Thiruchendur also a temple town, with a shore temple just at the shore, with protecting walls built by the Government from sea erosion!!! only difference is no story about thiruchendur being lost to the sea... and I think the temple is much recent than the M.Puram temples.. very nice beech.. public are allowed to surf in T.ur. clean beach.