how to make snow edges follow terrain?

[bigben]

So Ben ... you seem to have a lot of experience with snow for an Aussie! What's the deal?

I've hiked through snow in Scotland??

True, our snow sucks most of the time (we just don't have the elevation), but even with a little snow it has it's moments:
http://www.path.unimelb.edu.au/~bernardk/victoria/virtual/howitt.html
http://www.path.unimelb.edu.au/~bernardk/victoria/virtual/pieman.html

But otherwise I just tend to over-analyse pictures to figure out how to make more realistic renders   Tree Canopy maps actually give you similar distribution variations....
Alpine areas - rock laden floods clear river beds
Flat farmland - farmers tend to leave trees along rivers and clear everything else

[Harvey Birdman]

Well, I'll be damned. I thought the only thing down under that even started to look like a mountain was Ayers (sp?) Rock. Pardon my ignorance.

Ever do any climbing in New Zealand? I swear if I lived as close as you I'd fly there every summer for vacation.

[bigben]

Well, I'll be damned. I thought the only thing down under that even started to look like a mountain was Ayers (sp?) Rock. ..

Careful viewpoint selection    Our highest peaks are around the same as the UK.... there's just wee bit more flat land around them. My methylated spirits camp stove works just fine everywhere here  

NZ would be good though...

[bigben]

I was working on my Mt St Helens terrain for a bit and tried some of the new intersect underlying settings.  I don't have a render on hand, but I can definitely recommend giving the new settings a try. Favour ridges/gullies at a quick glance is an awesome feature and may reduce the need for flow maps (providing much better results). It may also be useful for creating masks even if there is no/very small displacement used to set the selection of terrain. Definitely one worth exploring. 

[Volker Harun]

I found it useful to check 'Terrain normal' when using intersect underlying.
It is easier to control.