The heating season has started — carbon monoxide and chimney fires climb from here

The furnaces are running now. Across most of the northern tier the first sustained cold of the season has arrived, and homes that sat idle since spring are drawing on heating systems that have not been touched in six months. That is the pattern behind the next few weeks of your workload, not any single forecast.

Carbon monoxide is the one to watch first. Cracked heat exchangers, blocked flues, generators run in attached garages and gas ranges used for heat all peak when the cold does. CO calls read as flu on the tile — headache, nausea, several people down in one house, a dog that will not get up. Treat the structure as the clue. If the story is that everyone in the building feels sick, meter on the way in and ventilate before you commit crews deep.

Chimney and flue fires follow the same curve. A season's creosote plus the first hard burn is the setup. These present quiet and go bad in the void spaces; pull ceilings and check the chase early rather than chasing smoke.

Ice is the other change. The first freeze-thaw cycles put black ice on bridges, shaded curves and the aprons where you stage. Expect falls, and expect the vehicle calls to cluster at the same handful of spots your district knows well. Scene safety on the roadway is the recurring risk here — the second crash takes the responder.

For dispatch and EM: this is the window where CO complaints, carbon-related medicals and weather-driven MVCs all rise together, and they compound on the first cold snap after a mild stretch. Watch staffing against that curve.

None of this is an alert for a named storm. It is the seasonal floor. Check detectors on your public contacts, salt your own ramps, and treat multiple-patient illness at one address as CO until a meter says otherwise. When your local weather service issues a specific warning, that overrides the general picture here — act on their numbers, not these.