This type of disaster is classified as a mass casualty incident.
Explanation:
Mass Casualty Incident (MCI) is the type of event that involves a large number of victims. However, there is no specific number to classify it. What is important is that the number of victims demands a response that is beyond normal standards, that is, a response that needs more resources than there are available.
The situation described in the question is an example of MCI. According to the description, several people are to be transported to local emergency departments. It is likely that the arrival of several injured people at the same time will overwhelm the system. Perhaps there will not be enough doctors, nurses, or equipment available to help everyone at the same time.
To me the key phrase is We found. That phrase makes it sound like it is a person speaking with another person, making We the pronoun for the un-named speaker.
