I'm working out the neccesities for an ariel video shoot in the Blue Ridge Mountains of North Carolina in mid-January. That is IF DJI ships me my Inspire by then.

A couple of questions.

1) Many of the vantage points will be above the altitude level of the Inspire meaning it will be flown below me into canyon-type areas. I liken it to someone flying down into the Grand Canyon perhaps. How does the DJI or GPS-managed UAVs handle going below their initial home set altutude? Should I expect problems?

2) Mid-January in the Blue Ridge Mountains will undoubtedly be snowy and daytime temperatures between 10F and 40F based on current conditions. What should I plan ahead for?

Thanks!

Don't know about flying below your home altitude point.  I wouldn't fly in snowy conditions (moisture on the motors and possibility with other electric components).  Light snow  may be okay but video quality will be compromised with snow melting on the lens. Colder temps will decrease the battery performance. I think the camera specs are rated to -10C (14F).

This is quite a relevant question.
If you fly the inspire from the top of a mountain or from a canyon ridge, will we have any problems flying it at negative altitude vs take-off level?

Interesting point about negative altitude.
But is it actually negative, as no doubt all GPS will probably use sea level as a minimum.
An inland location that is actually below sea level could be a problem.

You should not have an issue with the negative altitude.  The Inspire records the home point altitude at initiation and take off.  That is what it uses for RTH.  As far as low ambient temps go, keep your lipos warm, I use a cooler with a rice bag inside.  You can also keep them in your car or in your pants.  The craft should be acclimated to the ambient temps before flight based on my experience flying in Lake Tahoe in low temps.

Thanks for the advice all.