Why Your Car Dashboard Says It's a Lot Hotter Than It Really Is

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iStock

When you first turn on your car in the middle of a sunny day, chances are your dashboard probably says it’s quite hot out. Like, a lot hotter than it feels. There’s a reason why car thermometers don’t always seem accurate, according to atmospheric scientist Greg Porter at The Washington Post.

Your dashboard temperature reading actually comes from something called a thermistor, which is similar to a thermometer but instead of mercury, it uses electrical current to measure changes in temperature. (Remember that temperature is an indication of how fast or slow gas molecules in the air are moving around. The higher the reading, the greater the molecules' kinetic energy.) In a car, that thermistor is located just behind the grill in the front of the car. Therein lies the problem: Your car's temperature readings come from an unusually hot location.

Asphalt roads get really, really hot in warm weather (enough so that cities become significantly hotter than their greener surroundings in the summer), so a temperature reading taken just above the surface of the road isn’t going to be super accurate. Heat radiates up from the road—as you can see on particularly hot days when the highway starts to look shimmery—and the thermistor in your car picks up that excess heat. It’s like measuring the temperature of a large room by sticking the thermometer an inch away from the fireplace.

That doesn’t mean your dashboard temperature readings are useless. When it’s not as hot out, there isn’t much interference from heat rising off the road. It’s also more effective when you’re moving—if you’re traveling down the highway, it will pick up less heat radiation from the road than if you were sitting in a parked car. However, Porter warns, the thermistor isn’t sensitive enough to distinguish between one-degree differences, which can be dangerous if you’re driving in the winter and need to know if temperatures have hit freezing or are floating just above.

In short, as nice as it is to know how temperatures are changing from one destination on your road trip to another, take that dashboard number with a grain of (road) salt.

[h/t The Washington Post]

Storm Leaves Homes Along Lake Erie Covered in Up To Three Feet of Ice

Houses along Lake Erie's shoreline were pummeled with sheets of icy water during a storm last week.
Houses along Lake Erie's shoreline were pummeled with sheets of icy water during a storm last week.
John Normile/Getty Images

This past weekend, lakeside residents of Hamburg, New York, awoke to find their neighborhood transformed into a full-scale replica of Frozen’s ice-covered kingdom, Arendelle.

According to CNN, gale force winds produced giant waves that sprayed the houses along Lake Erie with sheets of water for two days straight, covering them in layers of ice up to three feet thick.

“It looks fake, it looks surreal,” Hamburg resident Ed Mis told CNN. “It’s dark on the inside of my house. It can be a little eerie, a little frightening.”

While the homeowners are anxious for the ice to melt, they’re also concerned about what could happen when it does.

“We’re worried about the integrity, of structure failure when it starts to melt, because of the weight on the roof,” Mis said.

He added that this is the worst ice coating he’s seen since he moved to the area eight years ago—but it’s not because they’ve had a particularly harsh winter. In fact, just the opposite is true. According to The Detroit News, warm winter temperatures have caused ice cover on the Great Lakes to drop from 67 percent in 2019 to less than 20 percent this year.

“Lake Erie typically has significant ice cover by this time of the year, and that protects the shoreline from these battering storms,” The Weather Channel’s winter weather expert Tom Niziol explained in a video.

The phenomenon has created another unforeseen issue for Hamburg’s coast, too: Tourism. The local police department posted a message on Facebook on Sunday, March 1, asking people to keep off both the “extremely unsafe and unstable” ice and people's private property.

[h/t CNN]

What is Lake-Effect Snow?

Tainar/iStock via Getty Images
Tainar/iStock via Getty Images

As you probably guessed, you need a lake to experience lake-effect snow. The primary factor in creating lake-effect snow is a temperature difference between the lake and the air above it. Because water has a high specific heat, it warms and cools much more slowly than the air around it. All summer, the sun heats the lake, which stays warm deep into autumn. When air temperatures dip, we get the necessary temperature difference for lake-effect snow.

As the cool air passes over the lake, moisture from the water evaporates and the air directly above the surface heats up. This warm, wet air rises and condenses, quickly forming heavy clouds. The rate of change in temperature as you move up through the air is known as the "lapse rate"; the greater the lapse rate, the more unstable a system is—and the more prone it is to create weather events.

Encountering the shore only exacerbates the situation. Increased friction causes the wind to slow down and clouds to "pile up" while hills and variable topography push air up even more dramatically, causing more cooling and more condensation.

The other major factors that determine the particulars of a lake-effect snowstorm are the orientation of the wind and the specific lake. Winds blowing along the length of a lake create greater "fetch," the area of water over which the wind blows, and thus more extreme storms like the one currently pummeling the Buffalo area. The constraints of the lake itself create stark boundaries between heavy snow and just a few flurries and literal walls of snow that advance onto the shore. The southern and eastern shores of the Great Lakes are considered "snow belts" because, with winds prevailing from the northwest, these areas tend to get hit the hardest.

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