You can choose to send an SMS to emergency broadcasters by selecting the 'Send SMS Notification' option. This is located underneath the distribution lists in the Attributes section.
Selecting this option will send an SMS that prompts people to check their emails. If you choose this option an SMS will be sent to all recipients on the distribution list/s that you have chosen. You can find information on distribution lists here.
You should follow agency rules when choosing to use this.