via West County Explorers Club: Having visited a couple of fire lookouts this year, I found them to be pretty fascinating places. In this age of electronically monitored everything, rangers and volunteers still head to the tops of mountains to scout for forest fires with nothing more than simply surveying gear.
When smoke is spotted, a bearing is taken using something called an Osborne Fire-Finder, basically a circular map and a sight on a rotating turntable. Once the fire’s bearing is recorded, it’s shared with other towers, who, if they are within visual range, also report a bearing. With a bearing from at least two towers, an approximate fix on the fire can be made. Using the line of sight across the circular map (the lookout tower is located in the center of the map) estimates of the fire’s location can be made if no other lookout is within visual range.
This video, about the Mt. Tamalpais fire lookout in Marin County, just north of San Francisco, is more about the view but I’ll hope you’ll enjoy it just the same.