I agree, it will almost certainly be open for at least a couple days for the simple fact that hunters have three days to report kills and then ADFG gives a day or two notice. I really wish I could go this year.They don't. I've never seen less than 24 hrs notice, and 48 hrs is more common. If they expect that the quota will be reached nearly immediately, they will either announce further restrictions or simply set the closure date before it even opens. HOWEVER, in my experience the early August portion of the herd crossing the Steese is usually heavy on the cows. No predicting caribou with any certainty, but the bulk of the bulls are often still trailing back into Zone 3. It may take a minute to hit quota.
I strongly urge anybody hunting this opener to act like any other hunt. Stalk within range and pick your shots with care. Just because you can see other hunters on the ridgeline and the clock is ticking, doesn't mean mean you need to try long or running shots. The wounding and loss rates on these hunts is embarrassing. If you see one herd passing through, there will be another.
This goes double this year because of the bull only restriction. The wildlife troopers will be at every trailhead stacking confiscated cows in their truck.
I've drug a couple dozen caribou back from the Steese. It's a great place, but I'll let you guys have it on the 10th this year.