Intrusive weather and news alerts

I've been an Android user (S6 and now S8Plus for more than 3 years, and this happened last night twice at about 3 AM and again about 8 AM: All of a sudden, a loud verbal alert with weather and news headlines blares out, scares the devil out of us. I can't figure out which program or feature is suddenly generating these, or more importantly, how to stop them.

Background: I have do not disturb set from 10 PM til 9 AM for all programs except alarm clock. I assume "do not disturb" should also mute weather alerts like storm center etc.. In any event I don't think this was generated by any weather app(s) since as I said it included news headlines in addition to weather info (precipitation has been detected within X miles of you).

Any suggestions or help would be greatly appreciated. Thanks in advance.