Introduction

The internet on June 7 2023 was full of pictures of New York engulfed by smoky air.

This was attributed to smoke from wildfires in Canada

https://www.theguardian.com/world/2023/jun/08/canada-wildfires-air-quality-preparedness

I thought it might be interesting to look at the satelite data in detail from Canada and particularly Quebec. This is available online from NASA

https://nrt3.modaps.eosdis.nasa.gov/archive/FIRMS/modis-c6.1

The maps below show the central point of each fire registered by the MODIS satellite using a censor with a resolution of 250m.

The maps can be looked at full screen in order to interrogate the data carefully.

Fires per day in Canada during early June 2023

June 3

June 4

June 5

June 6

June 7

Combined

Interpretation

The data are all available for closer detailed interrogation in the maps above. Here is a screenshot of a zoom to one area affected.

What seems clear is that the fires were not generally affecting much undisturbed forests. The centroids mainly fall on already cleared areas. In early June the vegetation is still moist from melted snow during the winter. These appear to be managed “cool burns” that produce large amounts of smoke but cannot spread easily into the surrounding vegetation. The fires appear from this to be the equivalent of Scottish Muirburn or the burning of grouse moors in the North of England. Part of some management strategy rather than uncontrolled wildfires. This is further reinforced by the duration. They do not last more than a single day in any region.

Journalists investigating the phenomenon need to ask the right questions of the Canadian forestry service.