Ah, I was assuming you knew a fair ammout about scripting..
Hmm..
I can answer your down blast from heli question okay.. There is another script (Rotar Wash, by vectorboson [spelling?])
It has options so you can change the type of wash, green/brown for grass, blueish for water and white for snow..
The readme file for the script (In editors depot) has all the info you need on this
As for the snow object.. I found it (A while ago) under
Empty > Camera > Snow
or
Empty > Objects > Camera Snow
or something similar.. Have a search about (make sure you have the editorupgrade102.pbo file)
Good luck
- Ben