When responding to a high-rise fire, firefighters must be most concerned with which of the following?

In responding to a high-rise fire, the primary focus on water supply is crucial due to the unique challenges presented by these structures. High-rise buildings often require substantial water flow for effective firefighting, which not only depends on the internal plumbing systems but also on the fire department's ability to establish a reliable external water source.

Firefighters need to ensure that they can deliver enough water to the required floors, which may involve using fire engines to pump water to significant heights through hoses or coordinating with specialized systems within the building, such as standpipes. Having an adequate water supply is vital for sustaining fire attack efforts and ensuring that firefighters can effectively manage the fire while also protecting occupants and containing potential hazards like smoke spread and structural collapse.

In high-rise situations, the other factors—wind conditions, access routes, and elevator operations—certainly play important roles in the overall response. However, without a reliable water supply, the firefighting efforts are greatly impeded. Thus, securing and managing water supply is of utmost priority when tackling fires in high-rise environments.