Some beach cliffs are sand.
Do not climb those.
You may be buried much too early.
Notice the fresh green vegetation on the newly fallen mounds at the foot of the cliff.
That was just a little while ago.
That could be you.
Some beach cliffs are glacial loess (compacted dust remaining after the glacier goes away).
Those are pretty solid.
And they make awesome pirate caves.
The 50 foot hanging vines also help with the awesomeness.