Denver residents are able to sign up for emergency cellphone alerts for the first time in two years after the city hired a new company to manage its notification system. Residents can opt-in by registering online to receive messages about emergencies such as local police activity, natural disasters and gas leaks via text message, email or a phone call by visiting member.everbridge.net/509490495488038/new. The new system is capable of sending messages to specific neighborhoods, but only to people whose cellphones are registered.