GFMC EARLY WARNING PORTAL: DAILY GLOBAL AND REGIONAL FIRE WEATHER AND CLIMATE FORECASTS & BACKGROUND MATERIALS
Sweden: Ground Moisture, Forest and Grass Fire Indices
The Swedish Civil Contingencies Agency (MSB) in cooperation with the Swedish Meteorological and Hydrological Institute (SMHI) provides daily updated fire danger maps of Sweden during spring and summer. There are three maps relevant to wildland firefighting, the grass fire risk map (relevant during spring), the forest fire risk map (relevant during summer) and the Fire Weather Index (FWI) map:
Grass Fire Risk
In Sweden the grass fire risk is present during the grass fire season, in spring after the snow has melted but before new green grass has grown up. The map has five different colors corresponding to the following conditions:
- Light grey: Snow covered ground, no grass fire season
- Orange: Dead grass from last year may burn if weather conditions cause the grass to dry up. The risk for grass fire is low or moderate. Local variations or rapid changes in the weather may, however, cause the grass fire risk to alter quickly compared to the prognosis
- Red: High risk for a grass fire. This prognosis means that the conditions are expected to cause such low moisture content in last years grass that a fire will easily ignite and spread quickly. Local variations or rapid changes in the weather may, however, cause the grass fire risk to alter quickly compared to the prognosis
- Green lines: There is still grass from last year but new green grass has begun to grow. The risk of grass fires decreases as new grass grows into the old
- Green: New green grass has grown up. The risk of grass fires is low
Forest Fire Risk
The Swedish forest fire risk is calculated using the Canadian Fire Weather Index (FWI) system of which more can be read here: http://cwfis.cfs.nrcan.gc.ca/background
The numeric values of the FWI are transformed into six different levels of risk displayed on the forest fire risk maps (FWI and HBV). The six levels of forest fire risk are the following:
1 = Very low fire risk. Corresponds to a FWI value of 0 – 1
2 = Low fire risk. Corresponds to a FWI value of 1 – 6
3 = Normal fire risk. Corresponds to a FWI value of 7 – 16
4 = High fire risk. Corresponds to a FWI value of 17 – 21
5 = Very high fire risk. Corresponds to a FWI value 22 – 27
5E = Extreme high fire risk. Corresponds to a FWI value of 28 or higher
An application is offered here:
