Not quite a master hacker, but still needs a harsh-ish term
This guy may not be particularly dangerous, but anyone who deliberately attacks something in a way that harms emergency management needs to have that enforced. If the people running the system are right that operations were impacted, his little stunt could have caused real damage to many people's lives.
Also, how painful would 36 months without a network connection be? On the bright side, I'd get to avoid those boring e-mails.