Visibility during fog.
 

On weather reports they will often say sometrhing like
VISIBILITIES REDUCED TO AS LOW AS 1/4 MILE.

I've been in fog that was so dense that I could not see an object 3 feet
from me. I'm guessing that would be ZERO VISIBILITY. But the question
I've always has is CAN THERE BE A NEGATIVE VISIBILITY? Like -1/4 MILE?
Or does it stop at ZERO?

Visibility during fog.
 

On Wed, 30 Jan 2013, wrote:

On weather reports they will often say sometrhing like
VISIBILITIES REDUCED TO AS LOW AS 1/4 MILE.

I've been in fog that was so dense that I could not see an object 3 feet
from me. I'm guessing that would be ZERO VISIBILITY. But the question
I've always has is CAN THERE BE A NEGATIVE VISIBILITY? Like -1/4 MILE?
Or does it stop at ZERO?

That wouldn't make much sense... a negative value would seem to imply you
were suddenly seeing behind you. As cool as that would be, I think it'll
take more than fog to get there...