A bank open for business

The word bank originates from a time when people dug a hole in a bank and hid their valuables for safe keeping.
If you search shorelines hit by unusually high surf you may detect something of value buried or lost a long time ago in the eroded beach bank. 
This photo is a good example of an eroded shoreline hit by a winter storm that I had an opportunity to search last year. 

Shorelines change all the time in areas that are hit hard by coastal storms, leaving behind excellent metal detecting opportunities if you are lucky enough to search them.
They are what I call a "Twofer" treasure hunting situation, an opportunity to recover something good either flushed out of the eroded bank or something washed up and deposited against the eroded bank.
Two opportunities you can take advantage of when you know how to search an eroded river or beach bank.
I always like to search the face of any cut beach or river bank first, as you are often the first person ever to search the exposed layers, afterwards I search the from the base of the erosion to the waters edge looking for flushed out or washed in goodies.
The older the area and more history connected with the site, the more chance you have of detecting and recovering something old.
You can also recover good stuff long after the initial erosion took place if you know what to look for.
The back of the beach, river bank or dune line will often fill back in as if nothing had ever happened, but returning sand hardly ever makes it back up to the highest eroded levels. 
If you see roots dangling high up on the bank, check out the lower beach opposite at low tide.
The higher the eroded bank the better your chances are of recovering older jewelry, coins or artifacts.