|Sacramento Valley Fall
Burn Report - 2000
Project Leader Don Schrukraft, Weathernews, Inc., Chico
The 2000 Sacramento Valley Fall Burn Report
was generally upbeat. Cooperative weather, few complaints and improvements to the
Internet-based forecasting system made for a good burn season, which began September 15
and ran for 69 days to November 22.
A total of 97,031 "equivalent" acres of rice were burned during this period, significantly more than in any of the previous three years (see graph).
The weather was more cooperative for field burning during the fall of 2000 than it had been for a number of years. The first frontal system to cross the valley during the fall burn arrived September 22. Temperatures dropped from record highs over 100 degrees down to 73, but atmospheric dispersion was insufficient for a significant amount of burning to take place.
The first major burn day occurred October 9 when the atmosphere became unstable and thundershowers spread through the Sacramento Valley. A total of 5,610 acres burned on this day, with no complaints and good air quality reported. Wet fields the next few days minimized burning after passage of the weather system.
October 20 turned out to be the biggest burn day of the season with 9,149 acres burned (8,234 rice acres). A passing cold front got burning started early that day. Light rain allowed burning to continue well into the afternoon. Coefficient of haze, a measure of air quality, was reportedly very good.
Another frontal system entered the Sacramento Valley on October 25, the second big burn day. A total of 8,300 acres were cleared for burning that day, but rain mid-day limited the actual amount burned to 4,227 acres. Off and on rain for the next six days limited burning to 176 acres.
After several days of sunny skies, the fields dried out enough to resume burning. It peaked November 8 and 9 when 9,708 acres were burned. Moderate burning took place the following two weeks when wet field conditions and widespread fog closed the season on November 22.
Only two "no burn" days were declared by the Air Resources Board (ARB). Unlike the last few years, smoke from forest fires and controlled burns had less impact on agricultural field burning in the valley. Smoke from fires in the mountains can sink down into the valley, causing very poor air quality and poor visibility. Anticipated controlled burns by the U.S. Forest Service and Bureau of Land Management may play a major role in the amount of field burning that takes place in the Sacramento Valley in future years.
The number of complaints from citizens in the Valley totaled 38 during the 2000 fall burn program. The ARB received only four complaints. While the number of complaints is not necessarily a measure of the success or failure of the program, it is good to see the number of complaints down from the last couple years.
The Internet was the primary means of delivering weather forecasts and meteorological information to program participants in a timely fashion. Weathernews established a fall burn web page to share information with the ARB and others involved in burning decisions. A weather forecast was issued each day of the burning season at 5:30 a.m. An updated forecast was made available to all program participants by 8 a.m. Between 8 a.m. and 9 a.m. Weathernews consulted with meteorologists from the ARB. By 9 a.m. each county was contacted with the allotted burn acreage. Meteorologists continued to monitor the weather and make necessary adjustments throughout each day.
The program is broader in scope than most people probably realize. Total acreage burned includes 77,394 acres of rice and 19,637 acres of other agricultural commodities, including orchard prunings and other field crops. Rice, almonds, walnuts and wheat account for 95 percent of the dry tonnage crop residue burned in the state. Rice and almonds account for 64 percent and 18 percent, respectively. The amount of other agricultural waste burned during the intensive fall burn season has remained relatively constant over the last several years while the amount of rice acreage has fluctuated. On days when atmospheric conditions cannot efficiently disperse smoke from burning rice fields, only orchard prunings are authorized to be burned.
A Model Program
The Sacramento Valley Agricultural Burn Plan has become a model program for other air pollution control districts in the state. Last year's effort again showed that effective smoke management from agricultural burning can be attained with a well-organized program. Burning was maximized on days of good atmospheric dispersion and minimized at other times. The result is limited impact of agricultural burning on the air quality of the Sacramento Valley. Forest fires and controlled burning in surrounding mountains have the potential to produce more smoke-related problems than agricultural field burning.