Flame icons: active incidents
Each flame on the map is an officially reported wildfire from the National Interagency Fire Center's WFIGS system (fed by IRWIN, the same pipeline dispatch centers use) or, in Canada, the Canadian Wildland Fire Information System. Bigger flames mean more acres; the color runs from red (0% contained) through orange and yellow to green (fully contained).
Zoom in on a significant fire and you will see a small arrow showing the current wind direction at that fire, one of the best clues for which way it may push.
Perimeters: the fire's actual footprint
The red outlines are official incident perimeters mapped by firefighting agencies, usually from infrared aircraft flights or GPS mapping by crews. They show where the fire has burned, not necessarily where it is actively burning right now.
Perimeters lag reality by hours because they require a mapping flight and data processing. A fire can be well outside its last mapped perimeter during a wind event, which is why perimeters are best read together with satellite hotspots.
Satellite hotspots: heat seen from space
Orange dots are heat detections from the VIIRS and MODIS satellite sensors over the last 24 hours. Satellites detect thermal anomalies roughly 375 meters across, so hotspots show where heat is concentrated even before a perimeter is mapped.
Caveats: satellites can miss fires under heavy smoke or cloud, and they sometimes flag industrial heat sources. A cluster of fresh hotspots outside a mapped perimeter usually means the fire is growing in that direction.
Smoke plumes and alert zones
The gray smoke layer comes from NOAA's Hazard Mapping System, where analysts outline visible smoke in satellite imagery each day. Light gray is thin, high-altitude smoke; darker gray is dense smoke more likely to affect air quality at the ground.
Dashed colored zones are active National Weather Service alerts: red-orange for fire weather, blue for wind, and pink-red for heat. Tap any zone to read the official alert text.
Frequently asked questions
Small or new fires often have no mapped perimeter yet. Perimeters require an infrared mapping flight or field mapping, which typically happens once a fire becomes significant.
Incident data refreshes every few minutes, hotspots update as satellites pass overhead several times a day, and every layer shows its own last-updated timestamp.
Satellites detect heat before an incident is formally created in the reporting system, and they also pick up agricultural burns and industrial sites. Persistent, growing clusters are the ones to watch.
Official sources
This guide summarizes the following government publications. Read them for full detail.
Keep learning
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