On 02/12/2010 11:03, aquachimp wrote:

The snow has exposed a curiosity. I took a photo, but it doesn't show
it adequately.

Where the snow had settled on the "new" area, the layer is thin.
Where the snow settled on the old area, it's noticeably thicker and
showing more signs of melting. That includes the areas of "old "patio
which I left intact to "frame" the new one, where the "old" was still
intact..

Anyone know why that might be.

I'll hazard a guess that the old stuff is higher density concrete slab
with a better heat conductivity and so very slightly warmer and sticky
for the snow when temperatures are sub zero for a prolonged time.

Thing to look for is next time it snows does the old stuff stay wet for
longer and then quickly build up whilst the new stuff still has loose
powder snow on it. My cast iron drain covers do something similar.

Regards,
Martin Brown

PS now 14" accumulated snow here in North Yorks and counting