CTO: Trigger email to everyone when internet goes down. Do this by EOD.
Me: OK
Later
How could I send email without internet.
Confused....

Well, if your email server is on the lan, you'll still be able to send/receive just fine, as long as the lan itself doesn't go tits up, and as long as you're only looking to alert lan customers.

Otherwise you could suggest text notification via Twilio. Have an external webhook that triggers when a ping fails for a specified amount of time or something.

Only option then is to get on e(mu)-mail.
Gotta buy some of those well trainable and trusted office flightless birds. Can't go without them in 2017.

@Kyliroth why flightless?
https://tools.ietf.org/html/rfc1149

@chadd17 that paper is amazing ;)
Flighted is also an option.

I recommend the modern office emu for in-house transportation of larger data, digital or physical, including people!
You got someone at the front desk wanting to get to R&D at the other end of your building? Emutaxi away!

Also the Dromaius Novaehollandiae can reach speeds of 30mph -- -- it brings hilarious entertainment and lunchtime wacky races which increases worker happiness tenfold. :D