Your Echo device comes with the CBC News Flash Briefing as the default news flash briefing out-of-the-box. Alternately, you can open the Alexa app to enable and rearrange the order to have CBC News always play first.
CBC News' national Flash Briefing skill can be either audio or video depending on the Echo device you own. The national Flash Briefing updates hourly, 24 hours a day and 7 days a week for the audio version, and 2-3 times daily on weekdays and at least once per day on weekends, for video devices.
CBC News regional Flash Briefings are only audio at this time and update at least once a day, typically in the morning (local time).