ETL: Add new text to the 3.1 first paragraph

Add this text to the end of the first paragraph for 3.1

Alerting authorities may choose to broaden the chosen event and alert terms for many reasons. For example, these include, but are not limited to…

• alerting for fast changing situations, where the event type is subject to change in updated messages over time (i.e. a “rain” event, changing to a “sleet” event, changing to a “snow” event and then back again, can be collectively referred to as a “winter storm” event)
• alerting to reduce message fatigue and confusion of an audience, where the audience might otherwise be subjected to different event terms for similar events