When a price “gaps”, i.e. no meaningful traded prices or committed quotes across a wide price range, [or what quants/mathematicians call “jump discontinuities“], then you know that we are in the eye-of-the-storm. See the oil chart below for today.

So, the question arises, “when do we know we are close to the bottom?” 

The simple answer is that we will not know immediately – it will take several attempts to keep taking the market lower. Only when sustained selling fails to have any further impact will we have a bottom – when people are exhausted and algorithms fail to impact prices. It may sound obvious, but when everyone is driven by fear, stating the obvious is a helpful way to restore sanity.