It's 8am on Thursday 13th and the weather data sheet for the last 24 hours could be seen as depressing.  Wednesday afternoon was warm and partially cloudless above 1500m with above freezing temps at 1800m (per by shaded thermometer).  South aspects turned to mush, with very small ski-cut slides of a 10cm slush layer on crust (car to bus sized sliding area on 30 degree slopes).  Overnight there was rain to about 1500m or so.  All meaningful snow gone below 1000m.  Depressing?  Perhaps for resort skiing holiday makers, not really so bad at all for the backcountry crowd.  The biggest downsides are 1. a(nother) big crust on higher altitude SE, S and especially SW aspects, 2. Not good at all for top-to-bottom touring (my favourite type).

But the positive side outweighs the negative.  In the last three day the barometer has fallen from 919mbar to 902mbar at 860m asl (see my chart). It is snowing in the alpine (above tree line, roughly above 2000m).  That snow is heavy and wet and by Friday morning about 20-25cm will have accumulated.  10cm came down on Tuesday afternoon and night when I was up there.  By Friday night the temperatures will have dropped dramatically to -15C at 2000m and by Monday morning we will have had about 40cm of new cold snow on the heavier wetter layer that has a much better chance of bonding with the crust formed during the warm period.

This is called 'right way up' snow.  Warm and wet snow, followed by cold and dry snow.  The reverse is a disaster.  However right way up snow is good, so long as there are no instabilities in the existing snow pack.  But check extra carefully the bonding of the new wet snow with the older crust on southerlies.  It will be about 50cm deep by Monday (that's a guess).  Yesterday it was about 15cm deep - see the south facing profile for 1965m above Tsugaike here.  Be conservative and as always, give it time to settle, dont hit the steeps on the first blue morning.

There's miles of terrain to benefit from this week's cycle.  There isn't just one lift served boot pack featureless 'peak' to hang all your hopes on.

Lots of time to type this morning as I sit here and watch it rain, waiting for the freeze that's coming.