After the new metal roof, solar water heater, and solar PV system were installed, the very last portion of the roof project was to get the insulation beefed up, which is just what we did.
The first thing the fellows installing the new insulation did was to install the bird box baffles, which essentially provide a channel for the air coming in from the vents under the eaves (called the bird boxes) to flow into the attic unimpeded and out the ridge vent. They hold back the insulation from covering the bird boxes. Once the baffles were in, they blew in the new insulation, and here it is.
It's pretty high now. And it works really well. On most nights, with outside temperatures in the forties, we were now losing one degree Fahrenheit in warmth inside the house. On nights where it dipped into the thirties, we were now losing only two degrees. After observing this for a few days, it occurred to me that we will probably be able to heat the house comfortably with a fire in the morning, and a fire in the evening, which means that our firewood should be easier to make last longer.
There is no telling how cold or severe a winter we'll have, although by all accounts, it should be a lulu due to another La Nina event, but I think we're in pretty good shape.
Better than I initially thought, anyway.