What is going on here?

We bought this house four years ago. But I have to say, I really don't feel like I know it all that well. I wasn't around for the house inspections when we bought it. My husband and son moved in while I was still teaching out west. Then I commuted for two years.

This week it was really cold, but sunny. My kitchen window faces south and so gets lots of sun. I noticed that there seemed to be steam floating by the window. I had seen it before, but decided to investigate it this time.

It wasn't the dryer vent. That goes out on the other side of the house, on the driveway side.   We rarely see the south side of the south in the winter. I put on my boots and bundled up. This is what I saw.

It is a plastic vent pipe. I assume it is from the furnace. Notice the icicles dripping down and that huge stalactite, no, a stalagmite rising from the ground. The dead ground cover and twigs on the nearby bush are all frost covered.

I remember now that a contractor we had in the house at the time we redid the upstairs bath had mentioned that the furnace doesn't use the chimney and that we might consider removing it. I imagine that when the old coal-fired furnace was replaced with a natural gas one, the venting was done in a simpler way.

So now I'm noticing all the neighbors' steam creating their stalamites and frosty bushes on a cold winter day.