Watching a forest for wildfire: a reference design

01What a forest watch must see

A wildfire observing site answers four questions for a forested valley: is there smoke, how dangerous is the weather, where is the smoke going, and can the people who must act be told in time.

The site in this design is a forested slope on real terrain. Camera masts stand on two ridges, a fire weather station sits in a clearing in the stand, and a private cell tower with an edge rack carries everything out of the valley.

Each part already has a counterpart in agency practice. Fire weather stations feed fire danger ratings that guide decisions on crews, readiness and the safety of firefighters and the public¹. The design fits into those systems rather than beside them.

Nothing in a remote forest can depend on a public network or grid power. The site is designed to keep watching, deciding and recording on its own, and to report everything it held once a link returns.

02Fire weather, measured the way agencies use it

Fire danger ratings depend on a small set of weather values, measured the same way everywhere. In the United States, fire danger rating stations report temperature, humidity, precipitation, wind and solar radiation every hour¹.

The interagency standard is precise about how. Wind is a ten-minute average of at least 600 samples measured at 20 feet, and temperature is an instantaneous reading each hour¹.

Siting matters as much as the sensor. A station should stand in a large open area, at least as far from trees as they are tall and ideally seven times that distance from dense, tall vegetation¹.

On a slope, the same standard asks for a south or west exposure, and it asks for the station clock to stay synchronised with Coordinated Universal Time¹. These rules make one forest's values comparable with the next.

The station also needs care. Fire danger stations receive at least one maintenance visit a year, and during fire season missing data must be acted on within three days¹.

03Seeing smoke from the ridges

A camera on a ridge sees a rising smoke column long before anyone on the valley floor. With two masts, the bearings from each camera cross at the fire, which turns a sighting into a location.

The cameras use an open profile for networked video, which covers streaming over an IP network and the pan, tilt and zoom control that lets an operator look closer².

Satellites add a wider view. A public system gives near real-time access to active fire detections, with the location, extent and intensity of fire activity³, and a daily national analysis maps fire and smoke from satellite data⁴.

Satellites also have gaps. For several hours in the late afternoon, during the peak burn period, no public satellite with infrared sensors provides data, which is why a mission planned for launch in 2029 aims to observe at that time⁵.

The simulator shows the geometry behind a ridge mast. A taller mast or a higher column pushes the line of sight further over the curve of the Earth, while hills in between can still hide the base of the smoke.

04Carrying the picture out of the valley

Video and weather are worth little if they stay in the valley. In this design the cameras and the station join a private mobile network on the tower, a kind of network that standards define for non-public use, often so that data stays within one organisation⁶.

An edge rack beside the tower reviews the video locally. It flags likely smoke, attaches the camera bearings and the latest weather, and sends a short, complete record instead of a continuous stream.

The rack forwards those records over whatever backhaul the site has, fibre where it exists and satellite where it does not. When the backhaul fails, the rack keeps watching and alerting nearby crews over the private cell, and replays its record in order when the link returns.

Air quality sensors near communities can join the same network. Lower-cost sensors are portable and easy to run, and they are best understood by comparing them side by side with reference monitors⁷.

05Smoke, warnings and the wider picture

Smoke reaches far beyond the fire. Particulate matter from vegetation fires is associated with respiratory and cardiovascular effects, and an international advisory system coordinates fire and smoke forecasts and observations for the countries that need them⁸.

A warning is only useful if every system can read it. The Common Alerting Protocol is an open, non-proprietary message format for all kinds of alerts, with geographic targeting, several languages and support for digital signatures⁹.

In this design each alert from the site is written in that format and carries its evidence: the camera bearings, the frames that triggered it and the fire weather at the time. The agency decides; the site supplies the reasons.

Nexus Observatory Inc. designs observing sites like this one so that what a forest site sees can be checked, shared and acted on by the agencies already responsible for it.