Re: Beep below 37 degrees F

["John Virnig" <john@xxxxxxxxxxxxxxx>]

Rob thinks he's got a stupid question:

> I've got a stupid question for the group: My 2001 330i beeps
and flashes
> the outside temperature when it drops below 37 degrees. The
book says that
> this is a warning for possible road ice.
>
> Up until this year I've always lived in the south (Florida and
Texas)
> where road ice wasn't a problem... but isn't 32 degrees the
magic
> temperature?  Or does German water freeze easier? :-)

Ice crystals can begin to form at this temperature which is why
the gong goes off.  Overpasses made of concrete (which does not
retain heat well) will accelerate any air movement underneath it
causing both the surface of the bridge overpass and the surface
of the road crossing beneath to cool and freeze quicker than the
surrounding pavement.  This is why you frequently see ice form
both on bridges and on the road under the bridge before it forms
in other places.

And it's not a stupid question at all.

John Virnig
'97 328is (for sale)

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