The foot of a primary sand dune near me has grown by about 3 metres (towards the sea) in 4 years.
The council still loves their signs, "stay off the dunes due to erosion", or similar.

I agree, the "generic" signs are a good thing. But the dunes are growing, not eroding!!

At first glance, it looks like they are eroding badly, but they are growing so fast that the next stormy high tide cuts into the front of the dune, and causes some collapse to the unstable but rapidly growing dunes.

Note: this is just an observation...