Just snow....lots and lots of snow for my trips
First trip was just a few days at the beginning of May: 5" one day, 8" the next
Second trip was the the third week of May: one day of hunting in the snow, then 22" and everything was shut down
Can't help with specific numbers. There are plenty of birds out there. There are also plenty of hunters. I've heard lots of stories of success and plenty of pictures.
Good luck if it works out for you to make the trip!