I have gone skiing twice at Baqueira Beret (in 1999 and 2000 so
my experience is a bit dated), and I had good conditions and great
skiing both times.

Like most European resorts, the snow is not as deep and powder
conditions are not as frequent as in the West of North America.
However, there is pretty reliable cover from mid-station upwards
from late December through the end of March. It is well worth
the five plus hour drive from Madrid to get your occasional
skiing-fix. It is even better from San Sebastian or the like.

If you are considering traveling to Spain to ski, the real draw
is probably the culture etc. There are a lot of top quality
restaurants and bars in the Val d' Aran so you won't be
disappointed.