Coroner Sheriff Payne told the hearing that Miss Blackman's death could not have been predicted.
He said the National Trust, which owns a stretch of the beach where the tragedy happened, appeared to be doing all it could to warn visitors of the dangers presented by the 100ft cliffs.
"Sadly, Charlotte Blackman died as a result of an accident. It was a sudden act of nature that nobody could have predicted at that time."
More top news
Mostly dry and sunny again, and warmer than Tuesday. There will be more cloud and more breeze over parts of Staffordshire and Shropshire.
Breezy in the north with occasional cloud and a little rain possible across the Peak District. Dry further south, sunshine and less breezy.
Plans for a controversial development on the site where King Richard III died have been given the go-ahead.