Describe Dream Country in the BFG

From the text:

She noticed immediately that they were now in an altogether paler country. The sun had disappeared above a film of vapour. The air was becoming cooler every minute. The land was flat and treeless and there seemed to be no colour in it at all. Every minute, the mist became thicker. The air became colder still and everything became paler and paler until soon there was nothing but grey and white all around them. They were in a country of swirling mists and ghostly vapours. There was some sort of grass underfoot but it was not green. It was ashy grey. There was no sign of a living creature and no sound at all except for the soft thud of the BFG’s footsteps as he hurtled on through the fog.