The PRIMARY objective of timely declaration of a disaster is to:

The primary objective of timely declaration of a disaster is to ensure the continuity of the organization’s essential services, which are the services that are critical for the survival and operation of the organization, and that cannot be interrupted or delayed without causing severe consequences. By declaring a disaster, the organization can activate its disaster recovery plan (DRP), which is a set of documented procedures and resources to recover the essential services in the event of a disaster. The DRP should include the roles and responsibilities, the communication channels, the recovery strategies, the backup and restoration procedures, and the testing and maintenance activities for the disaster recovery process1.

References = CISM Review Manual, 16th Edition eBook2, Chapter 9: Business Continuity and Disaster Recovery, Section: Disaster Recovery Planning, Subsection: Disaster Declaration, Page 372.