Moisture of extinction [Extinction moisture content]
n. The dead fuel moisture content at which the Rothermelís (1972) surface fire spread model predicts spread rate will fall to zero.
Moisture of extinction is a parameter of fire behavior fuel models. The use of the term in the Rothermel (1972) surface fire model is misleading because it is not designed to predict extinction; rather, it is included as a way to predict the effect of moisture content on fire behavior (through the moisture damping coefficient). The greater the difference between actual moisture content and the moisture of extinction, the smaller the moisture damping coefficient and therefore the greater the spread rate.