Winter night climbing

"If you aren't related to Nanook of the North, the time to come around here to climb would be late September to mid October - most years at that time it's sunny, cool but not cold, and bug-free."

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Your definition, please, of "cool but not cold." Please remember, some of us are from someplace south of north. My personal definition of "cool" is a temperature in the neighborhood of 50-70 degrees fahrenheit; "cold" is below 50 degrees.

And, down here in Georgia, it ain't hot until you can boil an egg inside your undershorts.

Now, having written all that, I will admit that the other day I explored an area near the Appalachian Trail about 30 miles north of my farm, and I spent most of my time walking around in some funny looking, ankle-deep white stuff that was more than cool to the touch. And next week, just before I hop on that airplane to Panama, I hope to make it up to the Smoky Mountains about 90 minutes farther north for a li'l bit of snow skiing.

That's about the coldest it ever gets around here.

Keep on (night) climbin',
Wild Bill from Dawsonville
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Yankee Transplants & Trees in Jersey, <just slightly Off Topic>

Mark, you grew up in what is considered “The Tri State Area”.
Gee, your one of us after all! <obviously a quality pedigree>

And yes, trees, at least good climbers, are rare in New Jersey. The south and its pine barrens are worthless, the industrial central area doesn’t have trees and the northwest woodlands area is largely privately owned and readily posted “No Trespassing”. I have found and GPS marked a few good climbers in the north west sections of the state. I have to drive an hour to get to them, but what the heck, you can’t have all the Central Jersey urban glamour of crime, pollution, congestion, AND trees too, eh?

Climbing in Minnesota must be stunning. I can only imagine. Perhaps some day my leisure travel will bring me to points a tad more majestic than the lower Hudson River.

Electrojake

P.S. Wild Bill, the annual Panama trip, with Abe and company? I’m curious, how many times have you done that, or is this a first?

Just wondering,
Ej

I have done some great climbs around the Princeton area. Most of it was on private
property but a few climbs were held in near by state parks.

A bear came across us while we were climbing just outside of Hackettstown, NJ. The view from 80' up in a Poplar tree was grand.

In the Pine Barrens I have located a few large oaks, but they can be difficult to find. Grab the canoe and waders. The trees are out there but as civilization grows our wilderness shrinks.

I look at scouting for trees as the admission price to be worthy enough to climb.

Good luck - tree tracking can be fun. Just don't carry 600' of rope.

"Your definition, please, of "cool but not cold." Please remember, some of us are from someplace south of north. My personal definition of "cool" is a temperature in the neighborhood of 50-70 degrees fahrenheit; "cold" is below 50 degrees."

Oh, okay...

It actually is mostly within the lower part of your definition of "cool", but can range up into the 60's and 70's pretty often. It must be said, however, that it is also perfectly capable of dropping below freezing at night at that time of year (and climbing to 81 two days later) - upper midwestern weather routinely defies prediction. I've done my share of boiling eggs in my undershorts (3 years in Houston Texas with regular fieldwork in the Big Thicket during the summer) - after 7 1/2 years up here I'm almost cooled off from that.

Originally posted by Electrojake
moss, your mighty clever: a Beach Climb vs. a Snow Climb.

Also...
Is the hazard your referring to in photo-1 of the Beech, nearby power lines?
Just wondering.

Electrojake
The Fair Weather Climber <grinning>

Ah, I'm not that clever but I'm glad you found the accidental pun.

You are correct the hazards are converging powerlines surrounding the tree on two sides.
-moss

I've been reading a bit about winter climate physics and got to thinking about Moss' report of the warmer temperatures as he went up the tree.

Temperature inversions (warmer air higher up) are pretty common in the winter; they're especially noticable when they trap smoke from wood stoves near the ground. Snow is very good at giving off infrared (nearly perfect blackbody radiator in physics-speak), and on a cloudless night that energy just sails off into space. The snow surface cools off a lot, and the air within a couple of meters of the snow surface cools off too. That dense, cold air just sits there on the ground - which means that you climb out of it before you're too far up the tree. The effect would be cancelled out by a moderate breeze - that would mix the air and lower the wind chill - but it could be pretty noticable (maybe several degrees) on a calm night.

I know. The southerners are thinking to themselves "Well whoopee, so it's 25 degrees up there instead of 20". We northerners will take what we can get.

Now I really wanna get up there on a clear, calm, moonlit night this winter...

Good read MarkF! I never thought about the physics behind ground temperatures. You talk about the winter cold air being heavier. Is there any physics you can tell us about the sizzling heat? Any differences in temps with altitude? Is it hotter above on a still summer day due to inversion?

Treeman wrote: "Is there any physics you can tell us about the sizzling heat? Any differences in temps with altitude? Is it hotter above on a still summer day due to inversion?"

Hmmm. A winter nighttime temperature inversion is pretty simple, but there are some other things going on in the summer.

First altitude: Other things being equal, it does get cooler with higher altitude, but given the height of a typical tree the effect is pretty small. When Steve Sillett climbs a 100 meter (about 330 feet) redwood, the temperature change from the bottom of the tree to the top due to the lapse rate is less than 2 degrees F (the rule of thumb is 1 degree C for every 100 meters, this is what meteorologists call the adiabatic lapse rate).

Summer daytime temperature inversions: From what I understand, the sort of inversions that you get in the daytime in the summer are a larger scale phenomenon having to do with air mass collisions and temperature profiles over a few thousand feet. They do a good job of, say, locking in the air pollution over the city of Houston (and making the air a lovely shade of brown), but a tree isn't tall enough to poke very far into them. On the distance scale of a tree, the air should be hotter close to the ground during the day -- but only where sunlight is getting to the ground to heat it up. In a forest, not a lot of sun gets to the ground (1-5% or thereabouts).

Summer nighttime inversions: The same physics that applies to winter nighttime inversions also works in the summer, with a caveat. The ground cools fast on a clear night, the air in contact with the ground also cools, and that cool air just sits there unless the wind blows it away. This is why clear nights are often foggy by the morning -- the air near the ground cools down below the dewpoint. The caveat is that the trees have leaves in the summer, and this blocks the ground's "view" of the sky. As far as radiating infrared, a canopy of leaves is a good bit warmer than the sky on a clear night, so the ground won't cool off so much in a forest.

None of this gets at the bigger issue with how hot or cold it feels. That has to do with energy exchange between the climber and her/his surroundings, and the air temperature differences are often a pretty small part of that. The biggest differences between the top and the bottom of the tree are sun and wind. The sun warms you up, and the wind cools you down. Tall trees often begin to stick up above the boundary layer (that layer close to the ground where the wind is slower due to friction with the ground), so it's almost always breezier up there. The wind cools you down less if it's hot and humid. Whether the top of the tree feels hotter or cooler in the daytime during the summer probably has a lot more to do with the arm-wrestling between the effect of sun and wind than with air temperature changes.

Sorry about all that. Asking a science prof for an explanation is like waving candy in front of a baby...

It looks like the board here has added you on as a sound scientific resource. Now if I can only memorize the "adiabatic lapse rate" term I might be able to raise some eyebrows if I could apply it with accuracy. I would have to really get high in a tree to get the full effect of that temperature change. Maybe Tengu out on the west coast could see that kind of change.

Ground friction on the wind facinates me. I often find myself comparing our air atmosphere against the thicker atmosphere of water. I can see in my minds eye the forces of a water current like a river against the bottom surfaces.

Continuing on the thought of ground friction effects on wind...

I was in a red oak in a wooded area yesterday during some really strong gusts. We had a front coming through late in the day that was pushing against some warm southern air.

During the hard gusts the leaves on the ground were barely moving. The upper canopy on the other hand was rocking and rolling with upper branches crashing together like giant deer antlers. In a nearby schoolyard the wind was down low whipping up a dust tornado and throwing debris around.

The thick stand of hardwoods was creating a protective effect from about 50ft. down. The tops thrashed around and the boles were moving but no damage done by the wind. There were a couple of good cracking sounds from breaking dead branches but that was about it.
-moss