I've replayed the video frame by frame and I'm calling it.

A SLATY-BACKED GULL is among the gulls at the river viewpoint
at Hammond Boat Basin.

It's a weird bird and I'm still willing to be talked out of it
but it clearly shows the white wing marks ON THE LEFT WING, and
not-so-clearly on the right. I did not get clear underwing
pictures, but there does appear to be a break on the left underwing
as well.

The orbital ring is dull pink and the iris is an ivory white. It
shows a dark smudge just in front of the eye and has a dark-lined
eye if you step back from it.

And then there's the whole streaky headed thing, not really
expected in a winter adult Western (I'd expect grayer looking
wingtips in a WxGW hybrid).

http://home.pacifier.com/~mpatters/bird/uggu/ugly_gull.html

--
Mike Patterson Alas, to wear the mantle of Galileo,
Astoria, OR it is not enough to be persecuted
celata at pacifier.com by an unkind establishment,
you must also be right.
---Robert Park
http://www.pacifier.com/~mpatters/bird/bird.html