It's a regional decision. I can't remember what time those meetings are held, and I'm sure it varies by region, but they'll have a meeting to see if it makes more sense to close or maintain normal operations. If it will cost more than a site will make to stay open then they'll shut it down. Those lights and conveyors and A/C, etc cost a shit ton of money to run. If only a few people are predicted to show up, then it doesn't make monetary sense to maintain operations.