But here's where it gets strange. I soon realized that the electricity was only unstable in about 2/3 of the house. In the front hall, the basement, the garage and the TV room at the back of the house, there was no fluctuation at all! I moved the microwave in there so we could heat up food for lunch, then ran an extension cord from the kitchen to keep the fridge turned on - no problem at all with the electricity in that one room. I could turn on the TV in there and the kids could watch videos, but upstairs in the bedrooms, it was hopeless.
Finally, at about 3:30 PM, power came on elsewhere in the house, and after an hour or so, I realized that the problem had somehow resolved itself. I have no idea what happened. The circuit breakers in the garage didn't flip off throughout any of this bizarre episode. I can only guess that the house was wired in a strange way, with different gauges in the two different parts of the house, and one gauge was sensitive to electricity fluctuations in a way the other one wasn't. There were no reported power outages in Ottawa, but there were plenty elsewhere in the province. Could the problems drawing on the power grid elsewhere have been strong enough to cause electrical surges in OUR house but nowhere else?
UPDATE: It happened again! On Saturday. Another windy day, another episode of flickering lights. This time I called Ottawa Hydro, and they sent a crew out to look at the power lines. They agreed that the tree branches were causing the problem, so they got out the cherry-picker and the chainsaw, and lopped off a good number of branches, which are now piled next to our driveway. Dean will trim them and saw them into fireplace-size logs in the spring. However, I also called an electrician to come to the house this week and check the wiring. I needed some small jobs done anyway - installing new light fixtures, fixing a broken wall switch - so I figured it was a good opportunity to have the wiring checked out at the same time.