Wildfire Glossary


Have you noticed that there are alot of Dry T-storms in your area when Wildfires get going?
Yes, dry thunderstorms are typical during the month of June and early July here in Arizona. "Dry" thunderstorms, for those who might not see these often, are high-based storms where there is convection, wind, and lightning, but precipitation that comes in the form of virga, rain that evaporates before it hits the ground. These are part of the engine that produces wildland fires in Arizona...providing two ingredients - wind for oxygen and lightning for ignition. High heat and low humidities are provided by typical weather patterns during the month of June, when the monsoon has yet to arrive.

The recipe for tinder-dry fuel starts way back in the month of November. If the deserts and foothills of the Upper Sonoran Deserts receive heavy rains during that time, there will be a stunning wildflower season but heavy growth of brush - fuels that will dry out later in addition to pesky non-native grasses such as red brome. These grasses do not belong in the desert, but were brought in by man, through cattle ranching, grazing and moving herds. Now we are dealing with their propensity to become wildland fire fuel and a method to carry fire through the desert. Often, native plants will dry out but naturally lay down. Some desert plants do not dry out at all, but retain water through small leaf or cactus. Exotic plants that have arrived here and taken to the desert will dry out but remain standing up, providing perfect fuels for fire.

The rainy season of 2004/05 was very heavy. Fuels grew to heights I have not seen since I arrived here 10 years ago. Grasses reached to waist level this springtime. We knew we had potential for formidable fire season, and it looked like it panned out - one of our desert fires (Cave Creek Complex) reached 240,000 acres.
Man does so much to contribute to the problems of the weather. We think the smallest thing such as introducing a different kind of plant to an area will not affect such a large area in the grand scheme of things. As you have pointed out Susan, though that is simply not the case. Our littlest of actions can have the greatest of consequences
Curious Susan in your travels with Severe Weather, have you ever recorded fire whirls and/or lightning from the smoke?