A look at the index activity from 2016 until Jan. 29, 2018, shows daily ranges — low to high — are small and about the same size. The general uptrend is not interrupted by days of significantly large daily ranges. It was a smooth, stable trend.
By February 2018 the nature of the trend irrevocably changes — in the extent of volatility and direction.
First consider the volatility. After February the market is dominated by large daily ranges. The daily range between the low and the high expands dramatically and it remains very large — particularly when compared to the daily ranges of the previous two years.
After February the nature of the direction also changes. This is relentless volatility with sharp moves to the downside, fast and short-lived rallies and more market collapses. There is no stable trending behavior. There is no reliable underlying trend.