What is the term for the ratio of the amount of moisture in a volume of air to the total amount of moisture the air can hold at a given temperature and pressure?

What is the term for the ratio of the amount of moisture in a volume of air to the total amount of moisture the air can hold at a given temperature and pressure?

• A. Dead fuel moisture
• B. Live fuel load
• C. Relative humidity
• D. Fuel stacking

Answer: (C)

Moisture in the air relative to what the air can hold at the current temperature and pressure is described by relative humidity. It’s the ratio of the actual water vapor present to the maximum amount the air can hold if it were saturated at that temperature, usually expressed as a percentage. This matters in wildland fire scenarios because higher relative humidity means fuels stay wetter and resist ignition, while lower relative humidity allows fuels to dry out more quickly and burn more readily. Relative humidity is different from other fuel terms like dead fuel moisture (moisture content of dead fuels), live fuel load (amount of living fuels), or fuel stacking (how fuels are arranged). So the term that fits this description is relative humidity.

Moisture in the air relative to what the air can hold at the current temperature and pressure is described by relative humidity. It’s the ratio of the actual water vapor present to the maximum amount the air can hold if it were saturated at that temperature, usually expressed as a percentage. This matters in wildland fire scenarios because higher relative humidity means fuels stay wetter and resist ignition, while lower relative humidity allows fuels to dry out more quickly and burn more readily. Relative humidity is different from other fuel terms like dead fuel moisture (moisture content of dead fuels), live fuel load (amount of living fuels), or fuel stacking (how fuels are arranged). So the term that fits this description is relative humidity.