Billings, MT / Fargo, ND / Rapid City, SD / Cheyenne, WY – Winter officially begins today as Montana, the Dakotas, and Wyoming mark the Winter Solstice, the shortest day and longest night of the year. In one of the coldest regions of the country, safety officials say the longest night of the year also marks a peak danger period inside homes—when carbon monoxide exposure risks are at their highest.
The Winter Solstice coincides with extreme cold across the Upper Midwest and Northern Plains, where overnight temperatures frequently plunge well below freezing. Heating systems often run continuously for days at a time, placing added strain on furnaces, boilers, fireplaces, wood stoves, and space heaters. During blizzards and winter storms, power outages can lead residents to rely on generators or alternative heat sources, further increasing risk.
Carbon monoxide is a colorless, odorless gas produced when fuel-burning appliances do not burn completely or are not properly vented. Because it cannot be seen or smelled, it is often referred to as the “invisible killer.” The Centers for Disease Control and Prevention reports that carbon monoxide poisoning sends tens of thousands of Americans to emergency rooms each year, with the highest risk occurring during winter months—especially in colder regions like the Upper Midwest.
Medical experts warn that carbon monoxide poisoning disables far more people than it kills, often causing permanent neurological damage. Early symptoms include headaches, dizziness, nausea, fatigue, and confusion. As exposure increases, symptoms can escalate to chest pain, vomiting, impaired coordination, loss of consciousness, and death. In cold-weather regions, symptoms are sometimes mistaken for exhaustion or illness caused by extreme cold, delaying treatment.
Fire departments across Montana, North Dakota, South Dakota, and Wyoming consistently warn that long overnight periods—such as those experienced during the Winter Solstice—are especially dangerous. Heating systems may run nonstop, vehicles are sometimes left idling in garages to warm up, and generators may be operated too close to homes during storms. Snow and ice can also block exhaust vents and chimneys, trapping carbon monoxide indoors.
Safety officials urge residents across the Northern Plains to ensure carbon monoxide detectors are installed on every level of the home and outside sleeping areas. Alarms should be tested regularly, and batteries replaced as needed. Residents are advised never to use grills, camp stoves, or fuel-powered heaters indoors, to keep vents and chimneys clear of snow and ice, to operate generators outdoors and far from windows and doors, and to have heating systems inspected annually.
If a carbon monoxide alarm sounds, officials say residents should leave the home immediately and call 911 or the local fire department from outside. Anyone experiencing symptoms of carbon monoxide exposure should seek emergency medical care without delay.
As the Upper Midwest moves through the longest night of the year, safety officials say the Winter Solstice is more than a seasonal marker. In one of the coldest parts of the country, it is also a reminder that carbon monoxide—the invisible killer—poses a serious and sometimes deadly threat when extreme cold, long nights, and nonstop heating collide.
