For three days we waited,
a bowl of dull quartz for sky.
At night the valley dreamed of snow,
lost Christmas angels with dark-white wings
flailing the hills.
I dreamed a poem, perfect
as the first five-pointed flake,
that melted at dawn:
a Janus-time
to peer back at guttering dark days,
trajectories of the spent year.
And then snow fell.
Within an hour, a world immaculate
as January's new-hung page.
We breathe the radiant air like men new-born.
The children rush before us.
As in a dream of snow
This is a curious  simile  that doesn’t quite work. Horovitz compares the immaculate, snow covered world to… a calendar without anything written on it. 
 
 The idea seems to be to compare the wonder of nature to the possibilities open to humans. I’d have just stuck with the ‘world immaculate’, personally.
New Year Snow