What's the chance the Cyclone rune of Sweeping Wind spawning a lightning tornado?
The description of the Cyclone Rune says that
[...]Critical Hits have a chance to spawn a lightning tornado[...]without specifying how high that chance actually is. Now Sweeping Wind itself stacks with critical hits and I barely remember being in a fight without it being stacked 2 (with Blade Storm 3) times. Is the chance for spawning a Cyclone equally high?
Short Answer: ~70%
Long Answer: I looked around quite a bit, and there doesn't seem to be any kind of definitive answer on this, so I thought I'd take a look for myself.
I did two trials following this methodology using my level 60 Monk:
- Turn off all numbers except for the Critical Damage numbers (makes it easier to see when you crit)
- Keep Critical hit around 10% so you don't crit too much.
- Use an ultra-slow ultra-low damage weapon (bought from Act 1 Normal Vendor)
- Use a very slow attack.
- Only count numbers that pop against indivdual creatures, multiple-hits means multi-tornados; too hard to count.
- Get Whirlwand to 3, start tracking crits. Play in SP so you can pause the game after each crit for tallying (rather than trying to keep it in your head.)
This methodology isn't perfect because the whirlwinds are much easier to see than the numbers (they stay around a lot longer.) Also you could do a much better job tallying if you were to record the gameplay, then tally the numbers after.
Trial One: Bridge Act 3 NM: 30 total samples recorded, 21 Procs, 9 Misses: Result 70% Proc
Trial Two: Field Act 3 NM: 27 total samples recorded, 19 Procs, 8 Misses: Result 70.4% Proc
Obviously we'd want further trials to be sure, but I feel good that I got the same results in both trials. If you feel like you're seeing less than that, try turning damage numbers off so you can only see crit numbers. Crits off Whirlwind or anything but your primary(energy building) attack do not proc. You can proc like crazy if you use dual weapons and are using a fast attack that hits multiple enemies.