Isn't it SOP to cover a field when snow/ice is expected?
Obviously, the expected accumulation matters. But it is much too early in the season for a large amount of snow to fall. And the ground is still too warm for the snow to melt and freeze even though the air temp might be around freezing.
So I would expect that while the field might not be perfect, the groundskeepers know how to make it the best it can be.
It doesn't help Denver one bit if it's a mess. They aren't a plowhorse offense anymore than the Rams are.