It *should* take around 1-2 seconds for an Onslaught explosion to clear up completely.
If it's taking 10 seconds or so, that means your frame rate dropped to single digits... hmm. (It's important to note, though, that in that time, only 1-2 seconds of actual game time pass, since the engine itself won't go below 30 fps. So, while the frame rate being that low clearly isn't a good thing, at least you're not being disadvantaged by this compared to having a higher framerate.)
The thing is, it's really hard for me to see how the whiteout effect could lower the framerate that much. I can see how other stuff that happens at the instant of the explosion could cause a dip, but the whiteout itself? It could happen if your graphics card is right on the border of having the game be playable (though I'd expect you to be seeing frame rate dips all over the place, in this case), but there's also a good chance it indicates a driver problem, which a driver update might resolve.
If you (or anyone else that has these long duration whiteouts) could chime in with more details, I'd appreciate it.
Huh. You know, I've never noticed a framerate drop before, and I thought that Alex said that the white out being rate dependent was a bug thats been fixed anyways. I'm a bit confused. Maybe that was fixed for the next version.
That's definitely fixed, and been fixed for a while. The old issue was that you could get 10+ seconds of whiteout in actual game time.
The way the game currently works is it the engine runs at at least 30 fps. So, for example, if your game is running at 3 fps, it'll be in slow motion and it will take 10 real seconds for 1 game second to elapse. If that happens, the whiteout (and everything else) would take respectively longer, and that's the "correct" behavior. The reason it works this way is to maintain the integrity of the simulation so that, for example, bullets don't start passing through things due to a frame rate dip.