How do you acknowledge multiple alerts via console?

@Mike Moniz is right, the best way to handle this is SDT (scheduled down time). You can setup a recurring period and any alarms opened during that time will not be sent out as notifications and will have a stopwatch icon on them to indicate that it's a planned outage. The system uptime alert should clear 1 hour after the device comes back online. It's odd that you're seeing them on Monday morning when the reboot would have happened over the weekend.