I've used powdered drink mix for snow dye before I've just never mixed colors. You're right about the wind effecting the powder but that's only when your applying it once it hits the snow it fixes. I've used it as a trail marker when getting boy scouts to the campsite in areas with lots of snow trails. I usually mix it with water and apply it with a spray bottle with an adjustable nozzle.

During training sessions I've used straight dry powder and poured it directly on the snow. If its windy you just have to hold the oppening of your container close to the surface, you lose some but it still gets the job done.

I'll definitely start another thread on the subject shortly.