Frost-Quake?!

I've been around for a long time, but I'm still learning about the weather!

I remember, for example, a conversation I overheard one hot summer's day between my aunt and her son, who had just installed a fan in her kitchen.

That feels cooler, she told him.

Well, you know, it's all in your mind, he answered. A fan doesn't change the temperature.

Well, I feel cooler, she replied.

I knew a fan made me feel cooler, too. But why? It took me years to realize it was due to wind chill. The breeze created by the fan makes us feel cooler because it evaporates our perspiration more quickly.

Then just last week, I discovered another interesting weather phenomenon: a frost-quake.

It was early evening and Terry and I had just finished supper. Suddenly we both heard a loud bang. My first thought was that a car had hit our house, as unlikely as that was. It would have to hit our car first - and we would hear a crash, not a bang. Then I wondered if a heavy object - perhaps a tree branch - had fallen onto the roof or the deck. To Terry, the bang sounded as if it had happened on the opposite side of the house. He took his flashlight and went out to investigate. He returned five minutes later. He had found... nothing!

Later on, he heard that our region had been hit by "frost quakes"!

Frost quakes are caused by

• moisture in the ground (our snow had all melted a few weeks ago),
• little insulating snow, and
• a sudden drop in temperature.

People all around our area heard it. I'm still puzzled... We heard a boom - but one meteorologist said that frost quakes can shake houses, like earthquakes do. I don't recall shaking. But if people all over the region heard it, does that mean a frost quake moves through the earth over a long distance? Or is it a small localized phenomenon? I haven't found an answer...

There is so much to learn about weather!