Welcome to the Alleghany Ice Machine!
Go back and read your Ernest Gann.
Between Pittsburgh and Philadelphia, there is always the probability of
icing nine months of the year.

vincent p. norris wrote:
Hm, so there's no provision for ATC to report to FSS when someone declares
an icing emergency?

That would seem to have been the case in this instance, at least.
But I recall that about 20 years ago, I encountered clear ice so bad
in a Cherokee that I was down to 80 kts with full power and could
barely maintain altitude; so I told ATC I had to land and diverted to
Williamsport, PA.
After I landed and had a cup of coffee, I went into the FSS to see if
the wx was improving, and along with reports of icing, I was told that
one pilot had been forced to divert (no airport mentioned). It took
me a few moments to realize they were talking about me!