Thanks Dave for your ideas, I've worked the original up into more of a finished piece but still welcome advice. I'll let you know after the event on Friday how the young people responded to the challenge...

in soft  silvery silence
fresh footsteps show in the glow
animals shelter in cosy homes
beneath branches crystal encrusted

who has left their trail
on this pristine path of piping
as though iced across a cake
for a giant’s birthday surprise?

their feet fall deep into drifts
under a great burden
progress slow through heavy snow
a hard path undertaken

further flakes fall from far above
swirl and skirmish like swallows
settle and smooth the surface
 a blanket for the sleeping wood

hard to see through dense trees
as brittle branches grab
with skeletal hands
and scratch skin like cold claws

blizzard breath whips my neck
drives ice into my eyes
frozen in a coat paper thin
flapping in the snow blown wind