Figure 5: The average NDWI, slope, humidity, temperature, wind and precipitation of Mackenzie County, Alberta during the fire seasons (May - October) 2005-2017, normalized to a range 0 - 100.
The NDWI (Normalized Difference Water Index) raster is relatively consistent and does not have any areas of particular interest, as there are no areas containing significant high or low values. As a result of this, the values contained within the above NDWI map are considerably intermediate in nature.This particular raster represents an average of five fire seasons from 2013-2017, which may account for the lack of variation. Additionally, particularly good or bad seasons are averaged out as a result of this.The water bodies of the area can be seen as they are either represented by no data pixels or have a very low value. In the end, the NDWI values have very little impact on the outcome since it is fairly regular.
There are four weather variables related to forest fire susceptibility in Mackenzie County, Alberta. These include humidity, temperature, wind, and precipitation, and can be seen in Figure 5. The data is derived from various weather stations in and around the county.
The humidity and temperature susceptibility values are very closely related to each other. For the majority of the county, these levels are medium to high, with the highest values being on the south-western and south-central borders of the county. This shows that these areas are at a greater risk to potential forest fires. For precipitation, a large portion of the county is highly susceptible to forest fires. These values are very high, especially in the centre of the county. The lowest values for these three variables are in the north-eastern corner of the county. This is most likely a result of the land cover, considering this area consists primarily of wetlands. This means that this area is not very susceptible to forest fires.
These trends are opposite to those of wind patterns in Mackenzie County. The susceptibility values are very high in the north-eastern section, and this spreads down to the south-central section. The rest of the county experiences relatively low wind values, thereby reducing its potential forest fire susceptibility.
Figure 6: The normalized raster imputs for likelihood MCE (multi-criteria evaluation) normalized to a range 0 - 100.
There are four variables illustrated within the above map protraying likelihood factors. These factors are represented by roads, settlements, lightning, and power lines. Overall, those areas in close proximity to the factors in Figure 6 are more likely to experience forest fires. For instance, there is a high likelihood that forest fires will occur in the south-east of Mackenzie County as a result of an increased likelihood of lightning in this area. Those areas in close proximity to roads, settlements, and power lines will also experience an increased likelihood of fire as well. The map of the parks in the county was omitted as there was only one park which occupied one single raster cell in the analysis.
Likelihood and Susceptibility
Figure 7: The computed likelihood and susceptibility to forest fires of Mackenzie County, normalized to a range 0 - 100.
The analysis of the likelihood of forest fire ignition is based on human variables, including settlements, roads, parks, and powerlines, and lightning strike density. As displayed in Figure 7, this likelihood is largely influenced by proximity to human settlements and roads. The highest values are those that are near roads or towns. This is highly contrasted by the areas in Mackenzie County that are not close to human activities, those of which have relatively low likelihood values. As a result, the major influence in these more remote areas are lightning strikes. These values vary across the county, with the south-eastern area having a medium overall likelihood for ignition.
The analysis for susceptibility to forest fires is based on moisture content (as seen in figure 5), weather data (as seen in Figure 5), and slope. These variables are combined in Figure 7 to display the overall forest fire susceptibility in Mackenzie County. It can be seen that there are no severely high risk areas, with the majority of the county having relatively medium or intermediate values. The area of lowest susceptibility is the north-eastern section, which corresponds to the wetlands that are present. The weather data appears to have the greatest influence on the susceptibility of forest fires in Mackenzie County.
Figure 8: The computed vulnerability to forest fires of Mackenzie County, normalized to a range 0 - 100.
The forest fire vulnerability of Mackenzie County combines the variables from both likelihood and susceptibility and is displayed in Figure 8. The final output is very consistent with the other figures, with the most vulnerable areas being those that are closest to roads and settlements and the least being the wetlands area in the north-east. However, it can be seen that the range of values is not as wide, as there are few areas that have either very high or very low vulnerability. This has generally condensed the values into having a relatively more medium vulnerability to forest fires. After considering all these factors, it is clear that areas that are directly under human influence are still the most vulnerable to forest fires. This encompasses a large portion of Mackenzie County.