4-year-old Milwaukee girl left in van overnight

[MechAg94]

https://wreg.com/2018/11/14/4-year-old-girl-left-in-van-overnight-after-vehicle-towed-to-city-lot/

Not quite the normal story.  The mother was arrested on suspicion of drunk driving.  Police got the 10 month old out of the car then called to have the mini-van towed.  Somehow they missed a sleeping 4 year old.  No one noticed her until the next morning at the impound yard.  

The National Weather Service reported temperatures at Mitchell International Airport were around 25 degrees around midnight -- with a wind chill of 14 degrees. The temperature dropped to as low as 19 degrees with a wind chill of five degrees around 7 a.m. When the girl was found, the temperature had edged up to 22 degrees with a wind chill of nine degrees.

They are lucky the child appears to be okay.  

[Hawkmoon]

I love how the article keeps mentioning the wind chill (with nice, low numbers to make it seem all the more dramatic) when the wind doesn't blow inside a closed mini-van.

Trump doesn't have any idea just how right he is about fake news.

[TommyGunn]

I love how the article keeps mentioning the wind chill (with nice, low numbers to make it seem all the more dramatic) when the wind doesn't blow inside a closed mini-van.*

Trump doesn't have any idea just how right he is about fake news.

*It seems to me that while the wind wouldn't blow  inside the van (unless windows were open)  the wind would suck the heat out faster than if the air was still .... 

[Hawkmoon]

*It seems to me that while the wind wouldn't blow  inside the van (unless windows were open)  the wind would suck the heat out faster than if the air was still .... 

In general, wind chill factor only applies to organic objects. Not automobiles.

https://en.wikipedia.org/wiki/Wind_chill

The effect of wind chill is to increase the rate of heat loss and reduce any warmer objects to the ambient temperature more quickly. Dry air cannot, however, reduce the temperature of these objects below the ambient temperature, no matter how great the wind velocity. For most biological organisms, the physiological response is to generate more heat in order to maintain a surface temperature in an acceptable range. The attempt to maintain a given surface temperature in an environment of faster heat loss results in both the perception of lower temperatures and an actual greater heat loss. In other words, the air 'feels' colder than it is because of the chilling effect of the wind on the skin. In extreme conditions this will increase the risk of adverse effects such as frostbite.

[MikeB]

In general, wind chill factor only applies to organic objects. Not automobiles.

https://en.wikipedia.org/wiki/Wind_chill

This is why even when it isn't actually "cold" outside shelter is one of the primary needs in a survival situation. Just keeping the wind and potentially water off of you makes a huge difference. The temperature doesn't have to be below freezing to get hypothermia, and with shelter it can be well below freezing and not as dangerous.

I would think that even a cursory search by officers should have found the young child. I'm amazed mother didn't ask about the child. Without knowing details of conversations that occurred it's hard to make actual judgements.

[freakazoid]

I wonder if she was asleep on the floor of the car in the back seat with blankets/coats piled on hiding her.

[Hawkmoon]

I'm amazed mother didn't ask about the child.

Perhaps she was more than a little impaired ...

[TommyGunn]

In general, wind chill factor only applies to organic objects. Not automobiles.

https://en.wikipedia.org/wiki/Wind_chill

I wasn't refering to wind chill..... Heat can be transfered through conduction, convection, and radiation.  The metal of the vehicle can conduct the heat outward,  where it can radiate,  which I doubt would be affected by wind,  but convection would.

I'm not sure this means the process would speed up or not.  Maybe I'm wrong .... I was really sorta wonderin' out loud. 

[Hawkmoon]

I wasn't refering to wind chill..... Heat can be transfered through conduction, convection, and radiation.  The metal of the vehicle can conduct the heat outward,  where it can radiate,  which I doubt would be affected by wind,  but convection would.

I'm not sure this means the process would speed up or not.  Maybe I'm wrong .... I was really sorta wonderin' out loud.  

The key point is that wind ("chill factor" or not) cannot lower the temperature to below the ambient. So if the ambient temperature dropped to 22 degrees F., the temperature in the van could not have dropped to lower than 22 degrees F. High wind might result in the temperature dropping ab it faster, but it can't drop lower than the ambient temperature.

Which is why I object to the sensationalist references to the wind chill factor, when the wind chill factor didn't affect the child at all. 22 degrees is cold enough. It's totally unnecessary to drag inapplicable terms into the story just to make it sound even worse than it actually was. Then, of course, the question becomes one of deciding whether the author of the story knows what wind chill factor is and deliberately wrote an exaggerated story, or wrote a story using terms he/she doesn't understand but used anyway. I'm not sure which is worse.

[cordex]

Most cars are so poorly insulated that the difference in speed at which it achieves ambient is essentially irrelevant in the scale of an overnight stay.

That must have been really rough on the girl.  Hope she was able to find something in the car to wrap around herself.

[230RN]

It is true that an inert object in the wind will not get colder than the still-air ambient temperature. (Neglecting the miniscule heating by friction of the air)

However,the vehicle was not an inert object.  There was a source of heat within it, that is, the girl's metabolism.

The girl's body heat ultimately has to be transferred to the ambient air around the vehicle.  This transfer would be slower if there were no wind than in a wind.  Heat tranfer, in general, depends on the square of the velocity of the transferring medium as well as other factors such as density of the medium, etc.

That's why the concept of wind chill factor was developed for humans in the first place.

Thus, technically, it would feel colder to the girl with an outside wind than without.  Whether this would be significant depends on  the actual numbers involved, such as clothing insulation, etc.

So while Hawkmoon is right in terms of the semantic impact of using wind chill factors for dramatic purposes, it is true that the girl would feel colder in the vehicle with an outside wind  than in calm conditions since the rate of heat transfer from her body to the outside world would technically be greater due to the outside wind.  Whether it would be dangerous or even noticeable or not.... depends.

In other words, the vehicle could be looked at as if it were another layer of clothing.

Terry

(1) For general reference, the rate of heat generated by a human is approximately the same as a burning candle.

(2) This link shows the relation between temp, wind velocity, and wind chill factor for humans for an area near me:
https://forecast.weather.gov/MapClick.php?lat=39.7836&lon=-105.1675&unit=0&lg=english&FcstType=graphical
It will only show graphs for the time you click on it.  Note they don't even bother calculating a difference above about 47°F.  This "factor" is based on type and amount of clothing for a given temperature and is, to the strictly technical mind, kinda flakey.  It kinda represents an approximate engineering solution for a genuinely scientific, precise physical phenomenon.  

[TommyGunn]

The key point is that wind ("chill factor" or not) cannot lower the temperature to below the ambient. So if the ambient temperature dropped to 22 degrees F., the temperature in the van could not have dropped to lower than 22 degrees F. High wind might result in the temperature dropping ab it faster, but it can't drop lower than the ambient temperature.

Which is why I object to the sensationalist references to the wind chill factor, when the wind chill factor didn't affect the child at all. 22 degrees is cold enough. It's totally unnecessary to drag inapplicable terms into the story just to make it sound even worse than it actually was. Then, of course, the question becomes one of deciding whether the author of the story knows what wind chill factor is and deliberately wrote an exaggerated story, of wrote a story using terms he/she doesn't understand but used anyway. I'm not sure which is worse.

Yes,  I get it won't make the car colder than the ambient. 

     Anyway it seems the girl survived basically fine.  I guess I'll stop trying to hyper-analyze the thing.

[brimic]

Wind chill only applies if you have bare exposed skin, are unsheltered, or are underdressed.
Its used mostly to make news stories about weather more sensational.
In Milwaukee, its a big deal when -40 wind chills occur. Go 200 miles north and actual -40 degree weather for a week every january is a real thing.
I've experienced both and I laugh at the panic over -40 wind chill, its not even remotely close to what its like in actual -40 weather.
In Milwaukee, most people have never heard of freeze plug heaters, in central wisconsin, its standard equipment. 

[MechAg94]

Evaporative cooling is one way to get below ambient, but regardless, it was still a rough night for the girl.