This gull was discovered by Haven Wiley at Jordan Lake in the piedmont of NC on Sunday, 15 Feb 2004. When I relocated it on 17 Feb, it was not with any other gulls for size comparison, but it's been described as being the essentially same size as nearby Herring Gulls. Any comments about this bird's identity are welcome! You may email me directly at email@example.com or post them to firstname.lastname@example.org. Enjoy!
Note (18 Feb 2004): It was just pointed out to me that in my haste to get these photos processed and online, I inadvertantly put the copyright date stamp as Feb 2003 when it should be Feb 2004! Sorry for any confusion. I'll try to fix that soon.
I've now received numerous comments about this gull and the general consensus (though not unanimous) is that this is a Glaucous Gull (Larus hyperboreus). Identifying Glaucous from Iceland Gulls (Larus glaucoides) can be problematic, but here are a few things to look for: Glaucous has a flatter head, "meaner" look, and a thicker and more substantial bill. Note that males are larger yet with blockier heads and longer bills, so this bird is likely a female Glaucous.
Adult Glaucous show no dark wingtip markings while Icelands often have a few dark wingtip marks. Glaucous also have broader wings than Icelands.
On Glaucous Gulls, the wingtips do not extend very far past the tail, as this bird shows here. On Iceland Gulls, the amount of wingtip extension beyond the tail is usually longer than the length of the bill. Also, as Mike Skakuj pointed out, wingtip extension is going to be exaggerated on a bird sitting in water more so than a bird standing on ground, due to the position of the wing.
There's a Double-crested Cormorant in the back of this photo, possibly giving some size reference.
It's a bit difficult to tell, but I think the orbital ring in this photo is a rich golden yellow, which is another field mark for Glaucous Gull.
Here is an updated link to Will Cook's photos of the gull.
Many thanks to many folks who have contributed to this discussion and pointed out various field marks!