XIV has overheated and a reversion to the mean is likely in the months ahead.
When prices become this stretched from the normal, the move tends to be quite violent with a panic decline.
2day Chart
This model shows similarity to XIV. Notice the sudden drop with no warning, and continuation lower:
Not much room for downside on this chart for UVXY. Price slowly grinding along support with time. Spike up likely within a few weeks.
2day Chart