Brian wrote:

One question I have is what is "warmer" air? If I climb to freezing
temps in the clouds (which I have done), is descending to an altitude
that is maybe 2C sufficient to prevent further icing? From my
experience, the answer appears to be that this is sufficient, but I'm
wondering if the surfaces are still cold enough to allow ice to build.

It sure depends on the time beeing in the cold. A surface which has
collected ice but sees 1°C or 2°C "warm" air or water will definetly
melt after some time.
A certain delay might be caused (as we learned) with subcooled
fuel-(tanks) as the mass is much bigger. (So far lasts my "theory", as
I posted the topic to learn from the cloud pokers)

How about the "Freezing Fog" which the METARS show regularly since two
weeks over here in Europe ?
We have a 0°C .. 5°C surface temperature with a stable high pressure
system on top. Variable winds of 2kts and morning / evening fog, with a
lifting during the day to max. 500 feet in haze. On top (in 3000 feet)
we need sun cream!

How dangerous is freezing fog in such a small layer ??