I don't recall hearing anything on the news the past two days about the
recent cold snap affecting the South Texas citrus crop. I doubt there was
much of an impact as the temperature didn't seem to get below the mid
twenties for very long, with little precipitation and no high winds. IIRC,
in the past, with most citrus damaging freezes, the temperature were in the
teens, with a lot of wind and precipitation that caused advective freezing.
Besides, anything that would have justified the MBA's raising citrus prices
at the big corporate retail grocery stores would certainly have been
repeatedly mentioned so that we would feel better about paying more today
for oranges from Chile.
:( Yeah, that's a bummer for sure...but surely do like the Valley Ruby
Red grapefruit--there's none other that compares...
Grandparents (and now aunt/uncles/cousins) have place in the vicinity of
Usually moisture helps rather than hurts -- dry cold is typically the
more damaging. Often they'll mist (particularly at bloom time) to keep
the water vapor in the air so it's more difficult for the air
temperature to drop...at least that's what I was always told...I'm a
wheat farmer and only know what I've picked up second hand. We're so
far away we don't get down to where Mom's family is often...last I was
in the area was in '98.
Anyway, thanks for the info...
Not always. I specifically said advective freezing, where "moisture" plays a
part, combined with wind. The resultant evaporative cooling below ambient
temperature causes the damage to the grove. With this cold front there was a
lot of cloud cover and it was apparently not cold enough, for long enough,
to cause radiational freeze damage.
OK, I'm not arguing, as I said, that's just what I was always told by
kinfolk down there...they were probably keeping it simple for the wheat
Dry cold is about the only kind we know up here and it's calm if it's
under 25 mph...
But how do you get cooling <below> ambient this way?
Anyway, I was assuming the air temps weren't cold enough long enough for
Simple fact - can't get colder than the dewpoint. By misting, they raise,
or at least hold the dewpoint. If they get significant evaporative cooling,
they're not misting well enough. With a high RH, evaporation is nil.
Well George, you could trot your ass down to the Rio Grande Valley and
become St George overnight by teaching them with that superior
An even "simple(r) fact" - Your ignorance of advective freezing is showing.
Have you ever tried to "mist" in a high wind?
I was going to just drop off here, but I think there's a semantics
problem...to check my memory I looked up advection -- "The horizontal
transfer of air mass properties by the velocity field of the
atmosphere". That's what I recalled. The effect of wind is to enhance
heat transfer, yes, but it doesn't cause the cooled object temperature
to drop below the air temperature...that's against thermo rules.
Sure, one can't keep all water in the air if it's blowing hard, but the
same principle holds...even an ice layer over the tree can be an
insulating blanket that helps if the air temperature isn't too cold too
long and it's not at the most critical juncture...
Anyway, not to get too carried away...
OK, I went and did a google for "freeze protection orchard grove" and
found a nice paper (http://www.smallfruits.org/Weather/frost_freeze.htm )
by The Southern Region Small Fruit Consortium that describes technology
and principles very well...
They also define the "advective freezing" and I see it is simply the
movement of sub-freezing temperatures into the area en masse...under
those circumstances there isn't much one can do. That's a nomenclature
not known to me previously and, as I thought, a semantics issue....we
weren't discussing the same thing.
Rules? ... tell that to somone who had an ill-timed, though relatively
small, investment in a citrus grove operation back in the oil boom, flush,
early 80's and wished like hell that mother nature would have indeed "played
by the rules". :)
So as to know how those $$'s went away so fast way, I brushed up on the
subject, but it has been a while.
In any event, evaporative cooling _can_ certainly "reduce the temperature of
plant tissue to below the air temperature".
Suspecting that Texas A&M would have a current interest, and something to
say, on the subject of protecting Texas' citrus groves from freezing, and so
you don't take my word for it, here you go:
(wish I'd had access to www back then!)
Indeed, the technique of spraying to ice the surface is used to prevent the
more dangerous formation of ice crystals in the cells of the blossoms or
fruit, where lower temperatures are required due to the depressed freezing
point caused by solutes.
Just to add some fuel to the fire:
I was *told* when touring the Ocean Spray facility in Plymouth, MA that the
reason they flood the cranberry bogs in winter is to protect the plants.
Apparently they can withstand being in frigid water or encased in ice, but
frost will damage them.
Testy , aren't we? Sounds like you jumped on your ass to try and save the
world from something evil on the horizon.
I said nothing about the wind, that's your addition. Tilt away in
ignorance, or look up what I told you. If the mist blows away, they're
not/can't be misting well enough to hold the dewpoint. Simple enough even
You quoted what I wrote, but obviously read what you wanted to see.
I absolutely agree, George .. since it _is_ an essential component of what
was under discussion, your "saying nothing about the wind" pointed
_directly_ to your ignorance of the subject
> Tilt away in
That's because when you take away your superior-than-thou attitude, there
was nothing left but ignorant conjecture.
"Misting" a citrus grove is a very complicated business if it is to be
sucessful. What you "wrote" is not even in the ballpark.
Kiss my ass again, George.
> The Christmas gumbo is on, the house smells good with the cooking for
IMHO, that sucks.
Here in SoCal, if you want snow, two (2) options.
1) Go to the mountains less than 50 miles away.
2) Get a truck and haul in 30-40 tons of the stuff.
The high today in Ohio where my mother lives reached a balmy 10F.
Here in SoCal, at the old boat yard, the sun was shining and the high temps
were about 68F-70F, even if it was in the mid 40's at daybreak.
Not to shabby for the winter season, can even lay fiber glass in this
Happy Holidays to every one who celebrates the season.
To those who don't, enjoy the time your way.
Had to run down to Sargent to drain the pipes and hit strong flurries
on the way back. Had sleet/snow mix from the time we left the bay but
by the time we hit Hwy. 6 it was really coming down. By the time we
hit BW 8 the overpasses had quite an accumulation. Back around 1960 it
had quit. Kids live near Dickinson and they are getting quite an
accumulation. How 'bout that - a white Christmas in Houston???
At noon yesterday (Friday 12/24) I was looking at nothing but grass on the
lawn. By 8 PM there was 2' of snow.
Merry Christmas to all.
Buffalo, NY - USA
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