How far to evacuate?

[Highlander]

(15 December 2013, 10:20)Scythe13 Wrote: 'The Rule of Thumb': If you can put your arm out with your thumb up, and squint, if your thumb is covering the area of effect, you're out of the threat zone. That could be quite some distance, depending how close you are to the area of effect.

...I have read this several times,..and for the life of me, I cant understand that

...anyway, your example was chemical,..please dont just run, not even from the direction the foaming mouthed people are coming from,.. wind can change or you might be in an eddy,.. first work out which direction the wind is blowing and move against it..... you can use your thumb for that...

How far,.. well it doesn't have to be very far at all, depending on the wind strength, and providing you have moved against the wind,...then the wind has helped to move the threat away from you,.. the foaming mouthed people are of no threat in that regards

Riots,... these are noisy affairs, they tell you to move to a distance where you can no longer hear the riot,.. that is usually considered a safe enough distance