Lots of people were surprised by the drop in BTC prices but it had been coming for days.
The signals were clear, it had been showing convergence on the MACD indicator from the 8th, while prices were still going up, the MACD started to register lower peak values. Then on the 17th the drop begun with BTC touching the highest resistance peak for the second time before heading down.
Here, we also see clear market psychology taking placing, Euphoria at the top, follow by anxiety as prices started to drop and continue dropping and finally fear, desperation and panic - as we can see a nice little gap in the prices indicating panic sell off.