Where is the difficulty in fighting forest fires in Chongqing? What "black technologies" are there to help put out fires? Why take "putting out the fire with fire"? On August 26, Zou Yu, member of the Party Committee and Director of the Political Department of the Chongqing Municipal Emergency Management Bureau, and representatives of forest firefighting officers and fighters from Gansu, Sichuan and Yunnan answered the press conference of the support team outside the city for the rescue of mountain forest fires in Chongqing. 
The press conference of the support team from outside the city for the rescue of mountain forest fires in Chongqing. Shitao map
How difficult is it to fight forest fires in Chongqing? Many ignition points, high temperature and complex terrain
"This year, Chongqing has experienced the most severe high temperature and drought since complete meteorological records." Zou Yu summed it up as "four most extremes".
First, the temperature is the highest. The highest temperature in Chongqing this year has reached a historical extreme, with the highest temperature in Beibei District reaching 45 degrees. Second, the longest time. As of August 25, Chongqing had 15 days of high temperature over 40 degrees, 8 days more than the 7 days in 2006. Third, the scope is the largest. In 2006, there were 29 districts and counties in Chongqing with high temperature and drought exceeding 40 degrees, and this year it reached 31. Fourth, the precipitation is the least. This year, the precipitation in Chongqing decreased by 70% over the same period, even less than in 2006. 
On August 25, the scene of the mountain fire "Decisive Battle at Jinyun Mountain" in Xima Street, Beibei District, Chongqing City. Xia Hongbo Tu
Such "four most" causes this round of fire extinguishing work in Chongqing to have three major difficulties: many fire points, continuous high temperature, and mountain-shaped landform load.
"High temperature mainly brings adverse effects in two aspects." Li Jiang, the instructor of the second squadron of Malkang Brigade, Aba Detachment of Sichuan Forest Fire Corps, introduced that the first is the smoke and roasting of vegetation by high temperature, resulting in an increase in the temperature of combustibles, which is extremely easy to burn. It is very easy for Shen to produce crown fires, and it is relatively difficult to put out fires. On the other hand, the high temperature scorched the firefighting team. Among them, two members of the Malkang brigade suffered heatstroke during the firefighting process, and two comrades were bitten by mosquitoes such as wasps, which was a great test for the firefighting team both physically and psychologically.
"The temperature is a great test for our team's commanders and fighters." Yang Jianjun, the captain of the Chongqing Garrison Team of the Gansu Forest Fire Corps, introduced that their commanders and fighters are all from the Qinghai-Tibet Plateau, which is more than 3,000 meters above sea level. Chongqing is 300 meters above sea level, with a drop of nearly 2,700 meters. meters, spanning 6 dimensions, with a temperature difference of nearly 30 degrees Celsius. At the same time, the mountains are high and the slopes are steep and densely forested. The vegetation on the entire fire site is thick, and some combustibles and weeds are intertwined under the forest, making it difficult to approach the fire site.
"Chongqing mountain fires have many fire points, and rescues are carried out in multiple fire sites at the same time, so there is a great need for rescue forces." Zhang Zhenlin, deputy director of the Political Department of the Yunnan Forest Fire Brigade, said.
It is understood that in the fire fighting in Chongqing, on the basis of the 100 people stationed in Chongqing in the Gansu Longnan Detachment in advance, with the support of the National Emergency Management Department, a team of 200 people from Sichuan and more than 700 people from Yunnan were dispatched to support Chongqing, which played a very important role. effect. At the same time, including front-line armed police, firefighters, party and government cadres, militiamen, and volunteers in various places, a total of more than 20,000 people participated in the forest fire fighting in Chongqing this time. 
On August 25, the scene of the mountain fire "Decisive Battle at Jinyun Mountain" in Xima Street, Beibei District, Chongqing City. Xia Hongbo Tu
Defend Jinyun Mountain and make meritorious deeds to reveal the scientific principle of "extinguish fire with fire"
At 8:30 on August 26, after rescue efforts from all parties fought hard, all the open fires of the mountain fire in Xima Street, Beibei District, Chongqing City, which had been raging for four days, were all extinguished. Among them, on the evening of the 25th, the "fire extinguishing" method adopted by the Yunnan Forest Fire Brigade played a decisive role in the extinguishing process.
What is "putting out the fire with fire"? 
Wang Lei, deputy director of the fire fighting and rescue headquarters and director of the combat training department of the Yunnan Forest Fire Brigade. Shitao map
"Tackling fire with fire is also known as the ignition tactic." Wang Lei, deputy director of the Fire Fighting and Rescue Headquarters of the Yunnan Forest Fire Brigade and director of the combat training department, introduced that this is a common method used by many major forestry countries in the world when dealing with forest fires. The characteristics are that it saves time and effort, the effect is more thorough, the fire disposal is more thorough, efficient and fast, and the safety of personnel can be kept in an emergency.
The main principle of "extinguish fire with fire" is to artificially ignite the fire head (fire line) to connect with the forest fire burning in the opposite direction, so that the joint suddenly lacks oxygen and loses the combustion conditions. Burn the combustible material in advance. After burning, the fire spreads and there is no combustible material. When the two fires meet or meet, they will automatically go out.
Wang Lei said, but the application requirements for this method are relatively high.
First of all, there must be suitable conditions, such as the geographical environment, vegetation, climate and other conditions are suitable. The geographical environment refers to the support, such as roads, rivers, lakes or artificially excavated fire roads, etc. Last night, the artificially excavated isolation belt was used for ignition. The key point of climatic conditions is the wind direction, and we must seize the favorable opportunity.
Second, there is organized command. This method requires very high organizational command and professional skills of the team. The ignition, combustion support, and control of the size of the fire must be very skillful, so that the entire ignited fire must be within the control range.
The third is that there must be a bottom line and safety precautions for spot burning. Try to keep other people out of the fire to prevent accidents.
Wang Lei said, "The effect of the whole completion is very good. In just 3 hours, the fire head of nearly 1 km was cut off."
These scientific and technological supports are behind the fight against the Chongqing mountain fires
This round of mountain fires in Chongqing has affected everyone's hearts. In addition to the rescuers fighting the fire with their lives, they also used a variety of scientific and technological supports in the fire fighting process.
"Helicopter swoops on fire in the air, providing a time window for ground soldiers to achieve ground-air coordination." Zou Yu introduced that the number of helicopters in the Chongqing Municipal Emergency Bureau's Aviation Emergency Rescue Corps has increased to 6 this year, and the one-time water carrying capacity is 3.5-5 tons, but due to multiple wildfires, with the support of the Ministry of Emergency Response, 6 aircraft were mobilized, and a total of 12 aircraft were involved in this fire fighting operation. 
Yang Jianjun, captain of the Chongqing Garrison Team of the Gansu Forest Fire Corps. Shitao map
"We used drones to conduct a comprehensive survey of the fire scene, laying the foundation for the formulation of the next rescue plan." Yang Jianjun introduced, and also used night vision devices, which can not only help survey the fire scene, but also play a role in the personal safety of the commanders and fighters. guaranteed. 
Li Jiang, instructor of the Second Squadron of the Malkang Brigade of the Aba Detachment of the Sichuan Forest Fire Brigade. Shitao map
"Technologies such as 5G communication means, night vision devices, and fire prevention communication provide guarantees for us to grasp the situation of the fire scene and the actions of the team." Li Jiang introduced that this is convenient for the commander to direct the action and ensure the personal safety of the firefighters. In terms of fire fighting methods, their common practice is to use water to put out fires, which is safe and efficient, and one-time fire fighting is not easy to reignite. In this regard, they concluded and innovated a set of fire extinguishing methods with water. Basically, each pump is equipped with a tee and a five-meter emergency pipe belt at the corresponding position. Once a fire occurs, the fire can be dealt with as soon as possible.
"Fire fighting operations include physical and chemical methods." Zhang Zhenlin, deputy director of the Political Department of the Yunnan Forest Fire Brigade, introduced that fire extinguishers and water guns are all physical in nature. In terms of chemical fire extinguishing, Yunnan Forest Fire Bureau has developed some modern and relatively applicable chemical fire extinguishing agents, such as life-saving bottles carried by firefighters. In terms of technological innovation, the Yunnan Forest Fire Brigade recently purchased a large-scale drone to put out the fire, which has achieved remarkable results.
(Original title "Chongqing forest fires have all been extinguished, fire officers and fighters explain the difficulties of fighting in detail")