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Hello,
I live right near Millcreek canyon. Every evening a wonderful refreshing wind starts blowing at my house. I am assuming it comes out of Millcreek Canyon. What I am wondering is what causes it to happen every evening like clockwork? Also, why doesn't it occur during the day?
Thanks, Cheney
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We get this question a lot actually and the explanation isn't quite a simple one but let's figure it out. We have winds coming out of the canyon at night because of the cooler air sinking and rushing down. During the daytime, as the land heats up, the air is rising. As the sun sets, the land cools off rapidly, an example of this is to just stand outside for a few hours from when around the sun goes down and you can feel how fast it cools off. As this air cools in the canyon it sinks. This sinking air rushes down and continues going downward and out of the canyon. As it moves down, it also accelerates, the Bernoulli principle talks about this in physics.
Bernoulli figured out that a liquid as it passes through a pipe that gets narrower (like a canyon and air is our liquid), that liquid will actually accelerate. As the air sinks down in the canyon and starts to flow out, the canyon is narrow, so the air is rushing through, and you feel a nice breeze.
During the day time, the land is heating, warm air is rising, not sinking like the cold air at night.
We also must mention the Great Salt Lake and the lake/land breeze connection which also is similar. During the night, the lake stays warmer than the land and we often experience a land breeze in salt lake. A link on the right can show you the lake breeze circulation and how it works. During the day time, the land gets warmer than the lake (just stick your hand in there and you realize it's colder than the air around you). As the air rises from the land, we form a circulation during the day and we experience a breeze coming in from the lake, or a lake breeze. The lake breeze circulation can be pretty strong and when it switches at night, it can get windy in the city.
Answered by KSL Meteorologist Dina Freedman.
