Bob:
<<<snip>>>
Asphalt paving was slippery wherever I drove. Does anyone
know why
that should be? The earth is not frozen and air temp had not
been below
32 for several days.
<<<snip>>>
Yes, Bernoulli effect. This happens when the temp is close
to the dew point. Wind blowing across trees and other
objects causes the vapor pressure to drop just enough that
the moisture in the air falls out as precipitation. This
can also cause the moisture to actually come as snow.
Another cause may be a very light almost invisible snow fall
which can happen when the air temp is above 32.
Very light moisture on the road is quite often slippery due
to fact that there's not enough water to flush the oil and
petroleum residue off the road. So you have water on top of
oil.
We had the same conditions here on Sunday morning going to
church. Just the pavement was dark damp, but the sidewalks
were not.
Blake
/// or try http://www.team.net/cgi-bin/majorcool
/// Archives at http://www.team.net/archive
|