Snow on the Hallelujah Mountains?

[ISV Venture Star]

Pandora has lower gravity (0.8g) than the Earth. This means that the scale height (see link below)

Scale height - Wikipedia, the free encyclopedia

is greater. So you need to be at a higher altitude to see a big change in pressure (and also temperature) than is the case on Earth. Higher values of T would also increase H. OTOH, the Pandoran atmosphere has a fair amount of CO2, and that would mean that the average molecular mass (M) of the atmosphere is higher than on Earth, decreasing H. Hmmm.