Two nights ago we lost gas pressure from the supplier due to the large area of the country hitting high demands on the system. It's kind of like blackouts in the summer with electricity. Our furnace was putting out heat but just enough to maintain about 68 degrees. Some of our neighbors totally lost enough pressure to satisfy the furnace thus it wouldn't fire up. This started about 9 PM and lasted until the next day when the local gas supplier went door to door to make sure everything was okay and lighting anything that needed manual restarting, like water heaters etc.
Most of the time when you see your exhaust stack spewing the steamy exhaust into the air you will say, there goes some more money down the drain, come on springtime or summer. When I took this I was just glad to see it period.