Division of Agricultural Sciences and Natural Resources / Oklahoma State University


Preparing to meet Mother Nature's heat

By Traci O’Hara

In Oklahoma, the land of unpredictable weather, there is no telling what Mother Nature will think of next. This state has seen it all--from sunny rays to rainy days. But when the rain stops falling and the wind starts blowing, Mother Nature sure knows how to heat things up.

Hot, dry weather is not uncommon in Oklahoma, by any means. And with land made up of forests and grasslands, wildfires run rampant when the wind comes sweeping down the plains.

"The wildlands of this state were created, or at least developed partially, by fire as an important driving force of the ecosystems," says David Engle, professor of rangeland resources. "Combustible materials, such as grasses, forbs, and wood from trees, are accumulated year after year as they die. These materials form a fuel component that will easily burn with or without man's help."

OSU agricultural and fire meteorologist, J.D. Carlson, working with the U.S. Forest Service in Missoula, Mont., implemented a computerized model called the Fire Danger Rating System for Oklahoma using the Oklahoma Mesonet.

The Mesonet is a network of 114 weather stations across Oklahoma designed to place timely and highly useful weather information in the hands of citizens. The fire danger model uses computerized data to alert fire managers when an uncontrolled fire is likely to break out. It can also rate the difficulty of control in that fire.

Engle says the Fire Danger Rating System rates the difficulty of the fire with two primary methods: weather conditions and the presence of adequate fuel.

"The right weather and the right fuels are needed for a fire danger situation," Engle says. "If one of these is conducive to fire and the other is not, there is no danger."

Generally speaking, fire is not a possibility when there are green fuels and the weather is dry, windy, and hot. Nor is it a possibility when there are dead fuels and the weather is cool and wet. However, when dead fuels meet dry, windy, and hot weather--bingo! The potential for wildfires skyrockets.

Fire danger based on the condition of fuels is rated by a number of indices. The spread component rates fire speed due to changes in wind v elocity and in dead and live fuel moisture content. The energy release component measures heat released in the flaming zone of the fire caused by variation in fuel moisture. The burning index, which is the most important fire danger index, rates the fireline intensity. This is where flame length is determined.

These indices give specific data on flame lengths and how fast a fire spreads. This information, combined with that of weather conditions available every 15 minutes from Mesonet stations around the state, will alert fire managers to potential danger ahead of time.

"This allows fire services throughout the state to know how substantial the risk of a wildfire is, the area of potential danger, and how large the wildfire will be," Engle says. "We're talking about saving millions of dollars just by being prepared for potential fire danger."

Another facet to fire, the opposite of wildfire, is prescribed burning. Prescribed burns are more easily conducted, not necessarily with the Fire Danger Rating System, but with the Mesonet information in general.

This Mesonet tower is part of a system of 114 sites located
across the state. The Fire Danger Rating System uses
Mesonet data to warn of dangerous fire conditions.

In addition to the fire danger model, Carlson is concentrating on improving the Fire Danger Rating System by working with a team of computer programmers to put a forecast model on the World Wide Web.

"When planning a controlled burn, it is important to know what's going to happen tomorrow or the next day, so we’re going to take some National Weather Service forecast products and put them on the Web," Carlson says. "The windspeed, wind direction, temperature, and relative humidity will be forecast in three-hour increments over the next 72 hours. This information is important in determining whether to do a burn or not, and also for preparations to contain the fire."

Carlson says a grant was just approved to help put new information about the Mesonet on the WWW so people can more easily access it.

"We received an $80,000 competitive grant from the USDA Agricultural Telecommunications Program," he says. "The idea behind this project is not only to put our agricultural and fire products on the WWW, but also to find other ways to bring this information to the public. "

This project also includes surveys of different user groups to see how they currently get weather information and how they would prefer to receive information.

This technology is still under development, but is available on the WWW on a trial basis. Some products are free; others are password protected.

"The technology available to us is almost beyond imagination," Engle says. "There are fire scientists and meteorologists around the world who are saying, WOW!"

With the technology available today--and more to come in the future--there is no doubt fire managers will be ready when Mother Nature sends her winds sweeping down the plains, spreading wildfires along the way.

Summer thunderstorms can be drought breakers, but
they are also known fire starters. Some 26,000 fires
are started annually in the U.S. by lightning when
fire danger conditions are right: combinations
of dead fuels and dry, hot, windy weather.


Agriculture at OSU Spring / Summer 1997
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