Skip to content

COLUMNS: Tracking wildfire with satellites and local knowledge

For those who use Google Earth regularly you are probably already aware of post wildfire images
11517675_web1_JimHilton

For those who use Google Earth regularly you are probably already aware of post wildfire images covering the Riske Creek area, in addition to a portion of the southeast corner of the Plateau fire complex.

Google also supplies a very easy to use feature: “Fire Activity Detected by MODIS.”

With a little practice you will be able to see where MODIS has located the many early fires started by the July 7 lightning storms.

Start by moving the date slide function to see when the fires first appear.

If you want more precise times click on the “wrench-like tool” on the upper right corner of the MODIS feature.

This will allow you to change the date and times of the MODIS images more precisely.

I found most fires were detected on July 7 by 11 p.m. PST (some as early as 9 p.m.)

While most of us know the Williams Lake fires were started around 3 p.m. (about six hours earlier than the satellite data), MODIS provides a colour-coded legend to help with the anticipated delay.

That is not bad considering the satellite is orbiting the Earth and may not be in a position to detect the first fire starts, as well as topography issues which complicate precise locations.

Don’t be surprised if the hot spots don’t all coincide with your recollection of the wildfire events and some of the locations do not make any sense (i.e. the two hot spots “in the water” of the southeast end of Williams Lake).

Users will have to accept the limitations of a fairly complex system that attempts to locate hot spots over a very wide area.

For those who are interested in a more precise explanation you can go to the Earth data site where they describe how the system was developed and why some of the hot spots may be out of place.

I have been using some data that includes both MODIS and VIIRS data and when I overlaid it on satellite images that showed active fires, in most cases there was a reasonably good agreement.

I think you will find the MODIS feature very useful for tracking the movement of the fires especially when there is a post wildfire image to use as a background and you can get ground confirmation of the fire events.

For example, a portion of the Riske Creek fire shows how a backfire worked to control one of the large, more aggressive fires.

The fire was north of Highway 20 between the Meldrum and Fish Lake roads and is clearly seen surrounded by fire guards.

When I first saw the post fire images it appeared that the fire burned up to the fire guards but as Gord Chipman pointed out as we drove by the area a few months later the east fire guard and Highway 20 were used as ignition lines to start backfires.

MODIS and VIIRS Earth data shows how the fire moved east after three lightning strikes on July 7 and was stopped by the backfires and crews on July 17.

Jim Hilton is a professional agrologist and forester who has lived and worked in the Cariboo Chilcotin for the past 40 years. Now retired, Hilton still volunteers his skills with local community forests organizations.

11517675_web1_copy_180418-WLT-RiskeCreekHilton