This week has seen a swift increase in volatility coinciding with the sharp downward move in SPX / SPY and equities in general.
To illustrate how short-dated vol rises much quicker and higher than longer-dated vol, notice the following performance comparisons for different vol-term lengths. Note that the comparison shows the percentage move off the recent mid-April vol lows in each vol index. The vol lows didn't necessarily land on the same day, though they were all in mid-April generally.
1. VIX9D rose 57.6% off mid-April lows
2. VIX rose +22.82% off mid-April lows
3. VIX3M rose +14.12% off 4/18/23 lows
4. VIX6M rose +11.76% off 4/18/23 lows.
Those buying shorter vol tend to see a much bigger move in options premiums. Shorter dated vol may mean (in this context) shorter-term VX futures or shorter-dated VIX options or it may mean short-dated SPX or NDX puts that have much higher risk for example. This bigger move is not without higher risk that always comes with shorter-dated options, which have exploded in recent months and years, rising to nearly 40-50% of total options volume on major indices per options-hedging flows experts.