Notice these expressions in the text. Infer their meaning from the context.
ducking back
manoeuvres
billowed
swathe
cairn of rocks
careered down
salt flats
ducking back: quickly going inside and then coming out
manoeuvres: military exercises involving a large number of soldiers, ships, etc.
billowed: filled with the air and swelled out
swathe: literally: a long strip of land of something; contextually: a land stretched with snow
cairn of rocks: a pile of stones that mark a special place such as the top of a mountain or a place where somebody is buried
careered down: descending the slope
salt flats: thatched roofed houses covered with snow