I was at Middle Creek this weekend, too, although not at the same time as Dad. His post has some good general information on the geese, and awesome photographs of them. The gathering of snow geese was in full swing on Sunday. I saw an estimate on the Game Commission's website that figured there were upwards of 50,000 geese in the area.
At one point, an entire hillside of geese "erupted" and took flight, going a short distance to a nearby field and congregating there. A small portion of the monster flock is landing in the picture above. I will post a short video of the goose explosion in my next post.
To contrast, here is one lonely goose, making his or her way across a small pond. This one was quite close, and like a lot of the other geese, showed little concern about the people "flocking" to see them :)