According to the forest fire risk grade, it is divided into several grades.

Grade four and grade five are the highest grades.

According to the National Emergency Plan for Forest Fire, according to the forest fire risk level, fire behavior characteristics and possible harm degree, the forest fire risk warning level is divided into four levels, which are represented by red, orange, yellow and blue respectively from high to low. ?

Red warning signal is extremely dangerous, and the forest fire risk rating is five. Combustible in the forest is easy to be ignited and spread rapidly, so it is difficult to put out the fire. ?

The orange warning signal represents high danger, and the forest fire risk rating is four. Combustible materials in the forest are easy to ignite, easily form a strong fire and spread rapidly, which is very dangerous. ?

The yellow warning signal represents high risk, and the forest fire risk rating is level 3, so the combustible materials in the forest are easy to ignite and spread, which has high risk. ?

The blue warning signal represents moderate danger, and the forest fire risk rating is Grade II. Combustible materials in the forest can be ignited and spread, which has moderate danger. ?

The classification of forest fire weather grades is based on the industry standard LYT 1 172-95 National Forest Fire Weather Grades (issued by the Ministry of Forestry1June 22, 1995). The standard * * * considers five meteorological factors of fire risk, namely: ① the daily maximum temperature in forest fire prevention period. ② Minimum daily relative humidity in forest fire prevention period. (3) the daily or early morning precipitation during the forest fire prevention period and the number of consecutive days without precipitation thereafter. ④ Maximum daily wind power level during forest fire prevention period. ⑤ The seasonal impact correction index of biological and abiotic phenology during forest fire prevention. Comparing the numerical value obtained from ①+②+③+④-⑤ with the standard value of forest fire weather grade, the forest fire weather grade is obtained. There is no danger at one level; Second-level low risk; Grade III moderate risk; Level 4 is highly dangerous; Level five is extremely dangerous.