For me the sign of a bull run is when bitcoin can gained +2000$ in just a single day , from 8000$ to 10,000$ in jus 24 hours is sign that bullrun has just started.
I dare to state if that something insane could happen in only 24 hours. Anything could possible in crypto arena, though. No one knows where is the market going next, however a wonderful news and and price can double in a short sequence of time or some of the big bagholders manipulating the market.