Burn Severity Datasets for British Columbia 1985-2019

Burn severity datasets for wildfires in British Columbia (BC) that occurred between 1985 and 2019 were created based on methodology and JavaScript code developed by Parks et al. (2018) with minor modifications to account for BC's growing season: pre- and post-fire scene selection dates were changed to June 1-Sept 30. Floating point geoTIFFs were created in Google Earth Engine’s code development environment using JavaScript; all other processing was completed using ArcGIS 10.6 & Python 2.7. 

Only wildfires >25ha are included in this repository. Fire perimeters from BC's Wildfire Perimeters - Historical spatial dataset were used to determine wildfire extents. Fire numbers correspond to the [FIRE_NUMBER] field within this dataset.

Please be aware that no field verification has been performed on this data.

Burn Severity Metrics

dnbr – differenced normalized burn ratio

rbr – relativized burn ratio

rdnbr – relativized differenced normalized burn ratio

Each metric  has also been run with an offset (see “_w_offset” directories), which includes pixels from a 180m buffer outside the mapped fire perimeter. This offset may help assess unburned areas within the fire perimeter as long as the cover types outside the perimeter are similar to the cover types within the perimeter.

Available Datasets

There are 5 raster and/or vector datasets available for each fire:

1.       Floating point geoTIF as exported from Google Earth Engine (GEE)

o   __.tif

o   ex. C10006_1985_dnbr.tif

2.       Integer geoTIF

o   Created from the floating point geoTIF

o   ___int.tif

o   ex. C10006_1985_dnbr_int.tif

3.       Integer geoTIF  clipped to mapped fire perimeter

o   Fire perimeter from the BC Wildfire Perimeter - Historical spatial dataset , with any internal holes removed, is used to clip the integer geoTIF

o   ___masked.tif

o   ex. C10006_1985_dnbr_masked.tif

4.       Reclassed clipped geoTIF 

o   Clipped geoTIF is reclassed using the thresholds in Table 1 below (from Parks et al. 2018).

o   ___reclass.tif

o   ex. C10006_1985_dnbr_reclass.tif

Table 1: Burn severity thresholds from Parks et al.

Low

Moderate

High

dNBR

<=185

186-417

>=418

dNBR with offset

<=159

160-392

>=393

RdNBR

<=248

249-544

>=545

RdNBR with offset

<=212

213-511

>=512

RBR

<=135

136-300

>=301

RBR with offset

<=115

116-282

>=383

5.       Reclassed burn severity shapefile

o   Reclassed geoTIF is converted into a polygon shapefile and the classification is converted to text (Low, Moderate, High); no smoothing is applied

o   ___reclass_poly.shp

o   ex. C10006_1985_dnbr_reclass_poly.shp

Known Issues

A small number of fires failed during the Google Earth Engine processing (see Table 2). These fires have no burn severity classification available.

Table 2. Fires without burn severity information available

Year

Fire Number

1985

N50175

N70035

V70088

1988

V50004

1990

C50050

K10013

R50117

V50055

VB0002

1992

K50034

1993

VB0007