During an mci, which section collects information such as weather reports, documents incident actions, and develops contingency plans?

The answer is "planning section".

We can define the MCI as any incident that drains the accessible on-scene assets at any given time.
National Incident Management System (NIMS) is a national framework that is utilized for the administration of MCIs, including acceptance of accountability of charge and assignment and coordination of such occasions as triage, treatment, transport, and arranging.
Planning section of MCI gives past, present, and future data about the occurrence of any incident; gathers information about climate reports, records occurrence activities, and creates emergency courses of action.