What is a critical factor in assessing a large fire upon arrival?

Assessing the wind direction is a critical factor when arriving at the scene of a large fire because wind can dramatically influence the fire's behavior. Wind affects how quickly the fire spreads, which areas of the structure may be at greater risk, and how the smoke and heat will travel. Understanding the wind direction allows firefighters to anticipate potential hazards, strategize the best approach to contain the fire, and prioritize the safety of personnel and nearby structures. While the availability of resources, building age, and size of flames are important considerations, they do not directly impact the immediate fire dynamics as significantly as wind does.