This is the gull in question at Ogden though the photos were distant and in heavy rain. I took these Sunday morning and pondered on Yellow Legged finally passing it off as LBB. On looking at the photos it has the head of a YL although the mantle is slightly darker . NK also had a bird he described as YL during the week which is possibly the same bird.
Looking at the photos now I would tend to go for Yellow Legged.
Thanks for the sun dog/halo info DCB.
BS