On the one hand, I get that it's a Sunday, and the CEO can't just write a mass email without approval from legal or other comms teams.
But on the other hand... It's Sunday. Unless you're tuned-in to social media over the weekend, your main provider could be undergoing a meltdown while you are completely unaware. Many higher-up folks check company email over the weekend, but if they're traveling or relaxing, social media might be the furthest thing from their mind. It really bites that this is the only way to get critical information.