Fires Seen by Satellite

The map

Each disc is a fire: the detections the VIIRS instruments on three satellites made within a few kilometers of one another in the last 24 hours, placed by the nearest of them, its area following the fire radiative power they add up to. The number on or beside a disc is its row in the table, the largest first. A hollow ring is a steady hot spot, a refinery flare or a landfill, say, and not counted. The diamond is this station; the rings are 100, 200 and 300 km from it, in the site’s distance unit.

A fire’s name is the incident the National Interagency Fire Center (NIFC) reports there, matched by place: inside or beside the perimeter NIFC has drawn, or close to where the incident started. A fire with no such match has no name. Where CAL FIRE lists the same incident, the fire’s card links to CAL FIRE’s page for it.

Each detection is heat seen from orbit, each satellite passing over a few times a day. Not every one is a wildfire, and none says where the smoke goes. The map is Natural Earth’s land, lakes and state lines, drawn once; only the detections change, every quarter hour as NASA FIRMS answers.