Tuesday, October 27, 2009

Colors Peak In Lower Elevations of Cumberlands


Pinnacle Overlook In Cumberland Gap NHP
Photograph by Harold Jerrell - © All Rights Reserved.

From magnificent Cumberland Gap National Historical Park to Breaks Interstate Park, autumn colors have been on beauitful display during the past week across lower elevations of the Cumberlands ( at elevations below 2000 feet ).

[ Note in Harold's photograph above, that a morning inversion with cool, calm air amid the Middlesboro Astrobleme Basin, has generated a layer of fog beneath an array of orographic wave clouds which have formed within much stronger air currents rushing across the Cumberland and Log mountains ].

Fog was also a key feature in Breaks Interstate Park this past weekend, as moist, cooling air drained downstream from John Flannagan Lake through the majestic, rugged depths of Breaks Gorge.

"The Towers" Beneath Fog-Capped Rims of Breaks Gorge
Photograph by Roddy Addington - © All Rights Reserved.

Visitors to Breaks Interstate Park may not think of it as being within the lower elevations, but most of the Park actually sits below 2000 feet.  The top of the jagged Towers, visible in Roddy's photograph above, is nearly 500 vertical feet lower in elevation than downtown portions of the city of Norton.  Yes, that is not often thought about!

The highest peak visible from the Park's many dazzling overlooks, is the massive Skegg Wall which caps Pine Mountain.  The upper portion of it stands, although hard to believe, not much above the water level of Bark Camp Lake in the High Knob Massif.

A hike up to Skegg Knob, adjacent to Skegg Gap and the massive Skegg Wall, is a difficult but rewarding experience.  On a clear day, as I have been humbled to observe, it's possible to see the High Knob highcountry capping the horizon upon looking across the upward sloping crest of the massive Skegg Wall.  An incredible site!

[ An old gravel quarry adjacent to Skegg Wall, in Pike County, Ky., has been GREATLY expanded in size during recent years, with the extensive quarrying of Greenbrier Limestone outcrops ].

Colorful Breaks Interstate Park - October 25, 2009
Photograph by Roddy Addington - © All Rights Reserved.

That Breaks Interstate Park sits amid lower elevations becomes obvious, when considering it contains the single water-level outlet for the 500+ square mile Russell Fork Basin.

It is here that water declared war upon rock!

It is here that a Mastercraftsman began the work of carving out the jagged, cliff lined, rock filled depths of Breaks Gorge from the northeastern end of Pine Mountain.

It is here that rock surrendered to water, and great palisade walls rose high above the turbulent, grinding, whitewater that still carves the Gorge today.

Kayakers Amid The Class IV-V+ Breaks Gorge
  Photograph by Roddy Addington - © All Rights Reserved.

By the time whitewater exits Elkhorn City, Ky., the Russell Fork River has dropped to 749 feet above sea level, 647 vertical feet lower than the summer pool elevation of John Flannagan Lake and 3474 vertical feet lower than the peak of the High Knob Massif.

The drop along the Russell Fork becomes significant through Breaks Gorge, where 140 feet of vertical drop per mile is average ( with a max gradient of up to 190 feet per mile ). 

This generates an American Whitewater rated Class IV-V+ run, which has become known as    "The Beast of the East."

The most dangerous commerically rafted river in the eastern United States.

Although upper reaches of Cumberland Gap National Historical Park ( NHP ) contain a good amount of elevated high terrain amid its wilderness backcountry, within the Martins Fork and Shillalah Creek basins, from Hensley Flats along Bailes Meadows to White Rocks, it is also surrounded by extensive lower terrain.

The Original Historic Cumberland Gap - Oct 26, 2009
Photograph by Harold Jerrell - © All Rights Reserved.

The original Cumberland Gap, as captured by Harold Jerrell, sits just over 1600 feet above sea level, nearly 500 feet higher than the 1138 foot benchmark in downtown Middlesboro, Kentucky.

Cumberland Gap Tunnel - Modern Passage - Oct 26, 2009
Photograph by Harold Jerrell - © All Rights Reserved.

Extensive efforts have been made to restore the "historic" Cumberland Gap to its former state, with building of the new Tunnels being a rather impressive feature of construction.

However, these are not even close to the awesome majesty which remains to impress those who visit great Cumberland Gap NHP.

Panorama of Middlesboro Basin At Night - October 2009
Photograph by Harold Jerrell - © All Rights Reserved. 

These large elevation variations within the Cumberland Mountains, generate multi-peak periods each autumn, as this website is illustrating ( with a global warming tendency toward later mean peaks being a dominant trend observed during the past 10-20 years ).  

During the 2009 autumn season, early color changes could be seen amid upper elevations of the High Knob Massif during mid-late September, with climax occurring during the October 10-17 period above 2700 feet ( locally before October 10 on some high, wind swept crests ).  A fairly "normal" season in terms of rate of color changes in the highcountry.

The week of October 18-24 featured peak conditions across lower and middle elevations,     with some color lingering this week across lower elevations, and within protected coves and hollows of the mountains.

And as you can see by the following pictures from photographers Harold Jerrell and Roddy Addington, there is MUCH color that remains which is not just "in the trees."

Aster Species In Morning Dew
Photograph by Harold Jerrell - © All Rights Reserved.

Bearded Tooth Mushroom ( Hericium spp. )
Photograph by Roddy Addington - © All Rights Reserved.

In general, and there are ALWAYS exceptions, colorations during 2009 seemed to be best across middle to upper elevations, with simply spectacular conditions observed within the High Knob Massif and along higher reaches of the mountain flanks of its extended landform.

Reference the following to view the glorious color climax:  http://www.highknoblandform.com/2009/10/high-knob-massif-reaches-glorious-color.html

[ The Kentucky ColorFall 2009 connection reports that this is the peak week across most of the foothills of the east, with lesser 45-60 percent change reported from around Dale Hollow Lake west toward Pennyrile Forest in western Kentucky ].



A Bit Of Geology

Prior to NASA satellites, USGS mapping, and Google, which have revolutionized the world, some use to think that Cumberland Mountain and Pine Mountain were one and the same, with Breaks Interstate Park at one end and Cumberland Gap NHP at the other.

However, that was certainly never the case! 

Cumberland Mountain is part of the extended northwestern flank of the High Knob Landform ( HKL ), and is physically separated from Pine Mountain by some miles.  Both the HKL and Pine Mountain are part of the Cumberland Mountain Group.

Pine Mountain marks the northwestern-most mountain ridge of the Cumberland Mountains, and of the southern Appalachians.

The HKL and Pine Mountain are both part of the great Cumberland Mountain Overthrust Block, with the northwestern mountain flank of the HKL being a geological mirror image of Pine Mountain.  This can likely be illustrated best by looking at a cross-section, taken across the Middlesboro Basin, which shows how major rock stratas are arranged beneath the surface.

Geological Cross-Section Across Middlesboro Basin
Courtesy of Kentucky Society of Professional Geologists

Rock layers on Cumberland Mountain dip northwest toward Pine Mountain, while those on Pine Mountain dip southeastward toward the rugged Cumberland Mountain arm of the HKL.

This forms a broadly concave basin, called the Middlesboro Basin, which actually extends far beyond Middlesboro itself along the entire length of the great Cumberland Mountain Overthrust Block ( into northern Wise & Dickenson counties ).

Note also how rock layers beneath the Powell Valley Anticline, the geological framework of the great High Knob Landform ( HKL ), are all arched in the cross-section above ( from Cumberland Mountain southeast ).

If the other side of this cross-section was completed and visible, its pre-erosional state would form a great mound of rock stratas reaching from rugged Cumberland Mountain and Poor Valley Ridge southeast to Wallen Ridge, Powell Mountain, and lovely Newman Ridge. 

It would show a consolidated mountain spanning the entire breath of today's Powell River Valley, such that prior to massive erosion most of Lee County, and adjoining counties along the winding Powell River, were once covered by a great mass of mountain.

The High Knob Landform ( HKL ), whose heart was eventually breached, or opened, to reveal the wondrous karst valleys and rolling landscape so beloved today.

The lofty backbone of Cumberland Gap NHP offers an ideal view of this great landscape, as illustrated by Harold Jerrell's gorgeous photograph below which looks across southern Lee County.

Looking Across the Opened HKL from Pinnacle Overlook
Photograph by Harold Jerrell - © All Rights Reserved.

[ The Pinnacle Overlook stands at about the same elevation as downtown Wise, with increases in elevation toward the northeast along the spine of Cumberland Gap NHP.  A substantial amount of highcountry exists within the confluence of Cumberland-Brush mountains, as the northwestern flank of the HKL develops a more complex geologic structure across central-northeastern sections of the National Park.

This will be highlighted in more detail within a later writing, so stay tuned to my website ].

In Summary...Reference Endemics Characteristics In My Main HKL Section for more details and graphics ):

http://www.highknoblandform.com/2009/09/high-knob-landform.html

The Cumberland ( Brush )-Stone-Little Stone Mountain crestlines mark the northwestern flank of the HKL, while Powell Mountain and Newman Ridge stand as what remains of its highly eroded southeastern flank ( southwest of the North Fork of Clinch River Gap, or The Divide, which separates the remnant massif of High Knob from the Wallen Creek Basin nestled amid Powell Mountain-Wallen Ridge ).

The High Knob Massif is the only large expanse of highcountry remaining today of this once enormous mass of mountain, that dominated the western front range of the southern Appalachians.

The complete HKL then consists of a remnant highcountry mass ( the High Knob Massif ), a dominant and elongated northwestern mountain flank, a prominent but more highly eroded southeastern flank, and a great calcareous heart of rolling karst valleys lying between these ruggedly majestic mountains.

This is illustrated by the high resolution NASA visible image below, where the HKL has been outlined in RED. 

The entire landform is visible, except for the very southwestern end, which runs back northwest along the Jacksboro Cross-fault to rejoin the southeastern & northwestern flanks ( near I-75 ) just southwest of Norris Lake in northern Tennessee ( amid union of the Clinch-Powell rivers ).

NASA Visible Satellite Image - January 11, 2004
RED Area Outlines The High Knob Landform

[ The mountain flanks being continuous with the High Knob Massif of today, and the breaching of the great heart of this landform ( the geologic Powell Valley Anticline ) occuring by headward erosion over time, so that today the apex of this process is marked by the V-shaped head of Powell Valley in Wise County, Virginia.

The name for this website is therefore, rightfully, that of The High Knob Landform after the remnant massif of highcountry to which it remains continuous today.

Reference this link for a more detailed explaination of The Name & Purpose Of This Website:

http://www.highknoblandform.com/2010/03/march-2010-second-week-spring-prelude.html  ].


Friday, October 23, 2009

Heavens Glow - A Pure Inspiration


October 23, 2009
Calcareous Core of High Knob Landform
Majestic Sunrise Glow Above Powell Valley
Photograph by Roddy Addington - © All Rights Reserved.

A fiery sky set the heavens aglow early Friday, October 23, as the sun began rising above the rugged eastern horizon of the great High Knob Massif, marking precious moments in time that were to be savored, treasured, and recorded by the gifted photography of Roddy Addington.

Captured from the floor of majestic Powell Valley,
this magical scene was pure inspiration!

Precious Moments In Time
Photograph by Roddy Addington - © All Rights Reserved.

Generated by a mixture of water vapor, ice, light, and invisible currents of rushing air that were lifted by the High Knob Massif in low-levels, and a jet stream at high-levels, this setting was a truly soul touching event!

Orographic Wave Clouds AGlow - October 23, 2009
Photograph by Roddy Addington - © All Rights Reserved.

Winds within the lower atmosphere were strong out of the SSE and aligned almost perfectly to generate long, horizontal rows of orographic wave clouds, which seemingly became longer and more fiery outward from the head of the great South Fork Gorge.

Embedded within these longer wave clouds were singular to multiple stacks of lenticular wave clouds, and various other forms of interest, as will be highlighted throughout this section and seen in every gorgeous photograph.

[ Note a distinct lenticular cloud with a round, lens-shaped top and sun illuminated, curved bottom within the center of this next heavenly masterpiece.  More examples of these cloud types will be shown in subsequent photographs.

Stacked lenticular clouds are also displayed beautifully within the first scene of this section, above the Maple Gap to Morris Butte of Powell Mountain of the High Knob Massif, where they appear to be partially hidden by streams of virga. 

Precipitation falling and evaporating aloft, which would play an interesting role in Roddy's final photograph of this scenic series ].

October 23, 2009
Cracker Neck of Powell Valley
Looking to South Fork Gorge of High Knob Massif
Day Begins With Heavenly Display & Mountain Serenity
Photograph by Roddy Addington - © All Rights Reserved.

This photograph by Roddy is the absolute epitome of mountain serenity with an imagination of families awakening to the dawning of a new day, amid a peaceful, pastoral valley set against a simply awesome backdrop of jagged cliffs whose rugged presence stand like guards at the edge of a great, sprawling mass of highcountry spreading outward for miles beyond the open, green meadows and cornfields to which it towers above!

[ In this case a true description of the High Knob Massif, the remnant highcountry of the High Knob Landform ( HKL ).

The High Knob Massif is the widest mountain from base-to-base in western Virginia, and one of the widest in all of the Appalachians. 

The mountain crestline rising upward along left side of the above photograph being dominated by jagged cliffs, which generate the undulations observed in its form.  Part of an array of upward stair stepping mountain ridges forming South Fork Gorge.

Reference Endemic Characteristics in my main High Knob Landform secton entitled:

What Makes High Knob Special?


What a wondrous setting
and way to begin a new day!

Numerous lines of orographically generated wave clouds can be seen emanating outward from the lofty mountain gap visible near center of this scene, high in upper reaches of South Fork Gorge, as air currents rushing across the majestic High Knob Massif are forced to ripple like great ocean waves amid the fluid atmosphere.

[ The lens-shaped lenticular cloud previously noted being an example of a mountain wave that is holding nearly stationary ( as will be illustrated below near the Grindstone Ridge Dome ).  It is harder to initially see, since so many other wave-form clouds and cloud fragments are present in the atmosphere ].

Other wave clouds, possessing notable variations in the direction of their axes, can be seen as up and down, or undulating, currents of air pass across the High Knob highcountry and reach upward toward a more SW-NE oriented jet stream of turbulent air.

Once again, as seems so often the case amid this great mountain landform, peaceful serenity hides a clash of dynamic forces!

Dynamic Forces Amid Supreme Majesty
Photograph by Roddy Addington - © All Rights Reserved.

Roddy's gift in capturing pictures is beautifully displayed above, as a host of dynamic forces work together to generate this magnificent display!

Bases of the lowest wave clouds are literally on fire, illuminated by the rising sun, to reveal mini-waves, rolls, and ripples which are embedded within the larger-scale waves.

Time lapse video photography of the above would further reveal that the longest wave clouds which Roddy captured in nearly every image are essentially stationary, or standing, orographic waves with sections trending toward lenticularis and stacked wave forms ( as highlighted below ).

October 23, 2009
Remnant Highcountry Mass of The High Knob Landform
Stacked Wave Clouds Adjacent To Grindstone Dome
Photograph by Roddy Addington - © All Rights Reserved.

Stacked wave clouds are visible in the above photograph adjacent to the great Grindstone Ridge Dome of the High Knob Massif.

Some of the most numerous can be seen left of Beaverdam Gap, and the convex Grindstone Dome ( where the rising sun has the horizon GLOWING with incredible brightness ), with numerous pinkish wave clouds stacked atop each other.  Simply INCREDIBLE! 

Less visible, and not fully illuminated by the sun, is a distinct lens-shaped cloud which is grayish in color, just beneath those pinkish stacks of clouds.  This is a mountain generated wave cloud which has formed lower to the summits.

[ The High Knob Massif is one of the most prolific generators of orographic cloud forms in the southern Appalachians, with a unique ability to develop wave form clouds on essentially every direction of the compass.  This is related to its atypically wide base-to-base widths, and good exposure, which act to perturb flow fields and dramatically impact climatic conditions ].

The Grindstone Dome plunges 2000 vertical feet within only 0.8 air mile, to represent one of the greatest short distance elevation changes across the entire western expanse of the Appalachians.

It's 3821 foot summit stands 402 vertical feet lower than the peak of High Knob, and can actually be looked down upon from the open expanse of High Knob Meadow.

It dominates the view from scenic Powell Valley Overlook, along U.S. 23, and often is a forcing zone for multiple, stacked cloud layers ( especially on SW air flows which must funnel upward through the Valley Head ).

I could teach a meteorology class, or perhaps even an entire course, on this wonderful set of photographic scenes, since every gorgeous picture by Roddy offers a multitude of unique cloud forms shaped and sculptured in multi-dimensions.

The entire setting being forced by a dramatically diverse mountain landform and its interactions with dynamic jet streams of rushing air ( at both lower & upper levels in the atmosphere ).

October 23, 2009
High Knob Massif
The Natural Classroom In All Its Glory
Photograph by Roddy Addington - © All Rights Reserved.

How could precious moments in time, such as these so beautifully captured by Roddy on this morning amid the open, calcareous heart of the great High Knob Landform come to an ultimate conclusion?

Sunrise Bow Ends Glorious Dawn Color Display
Photograph by Roddy Addington - © All Rights Reserved.

With a sunrise BOW adjacent to the plunging northwest slope of Powell Mountain.

How else could such a GLORIOUS
dawn conclude?



Wednesday, October 21, 2009

Sparkling Autumn Morning In Powell Valley


Cracker Neck of Powell Valley - October 21, 2009
Photograph by Roddy Addington - © All Rights Reserved.

Sparkling like diamonds, a frosty cold autumn morning amid the majestic Cracker Neck of Powell Valley is illuminated by early rays of the rising sun, as captured through the lens of photographer Roddy Addington.

Pristine, cold, with a tinge of wood smoke to flavor the morning air, a low-lying fog spills outward from the mouth of the great South Fork Gorge of the High Knob Massif to mark a plume of cold air draining downward from the highcountry.

Jagged Mountain Ridges Rise High Above Cracker Neck
Photograph by Roddy Addington - © All Rights Reserved.

Mountain ridges capped by jagged cliffs, riming South Fork Gorge, hide the sprawling highcountry of the Big Cherry Basin, which reaches northeast to the 4223 foot peak of High Knob.

Such a peacefully majestic scene, and seemingly "quiet" conditions, masks what was actually a very dynamic situation marked by large, impressive vertical weather gradients!

The overnight hours of October 21 featured extremely dry air amid the highcountry far above Powell Valley, with dewpoints in single digits above zero being common at the summit level of the High Knob Massif.

Dewpoints are a measure of the moisture content of the atmosphere, with very low dewpoints of between 0 and 10 degrees Fahrenheit being indicative of extremely dry air.

Low dewpoints indicate that the air has a potentially large cooling capacity, since under ideal conditions air temperatures can drop to the dewpoint.

Saturation occurs when the air temperature reaches the dewpoint.  Such a union is marked by the often magical appearance of condensed moisture, such as the frosty fog captured this morning by Roddy Addington as it spilled outward like a great stream of water from South Fork Gorge into Cracker Neck of Powell Valley.

Morning weather maps revealed the setting, as depicted below by the initialization ( or initial data input ) run of the NAM terrain model.

NAM Model Analysis at 1200 UTC ( 8 AM ) October 21
Image Courtesy of the Unisys Weather Processor

High pressure was centered over southwestern Virginia, with very dry air indicated by the pinkish colors on the chart in the lower right panel above. 

Note in the upper left chart that air temperatures around the 5000 foot level in the atmosphere, or at 850 mb, were in the 50s.

This was indeed the case, with morning temps at the summit level of the High Knob Massif in the upper 40s to lower 50s.

The lower 50s.  Think about that!

There were 20s to around 30 degree readings, with HEAVY frost on the Valley floor seen above in Roddy's photographs.  With Fog to boot! 

How could FOG and FROST form with such warm, dry air above?

The Big Cherry Basin of the High Knob Massif is a major cold air drainage and pooling area, as air drains off the 3500 to 4223 foot mountain ridges that ring the basin.  By the time air reaches the 3120 foot water level of Big Cherry Lake, it has dropped 1103 vertical feet from the peak of High Knob standing at the basin head.

[ Imagine how cold it can get up there on nights with snow cover, when the lake and wetlands are frozen over beneath a blanket of whiteness, with calm winds, radiational cooling in low dewpoint air, and downslope drainage off elevations as high as 4223 feet ].

A photograph from early September 2001 can be used to illustrate the layout of Big Cherry Basin.

Looking Across The Highcountry from High Knob Meadow
Photograph by Wayne Browning - © All Rights Reserved.

South Fork Gorge sits in between the Huff Rock peak and Morris Butte peak labeled in the above photograph, with the Valley floor from which Roddy took his majestic pictures located adjacent to where Morris Butte plunges downward ( below any point visible in the above picture ).

The solid black line in the above picture traces the approximate rim of the Big Cherry Basin, which sits completely above 3000 feet and represents the largest basin of its size in the entire 150+ air mile expanse of the Cumberland Mountains ( the small photograph above not doing it's large size justice ).

The Big Cherry Basin is unique for many reasons!

[ The Big Cherry is one of numerous highly elevated basins within the great High Knob Massif, as I briefly detail within the following section of my website:

High Knob Landform - Glorious Color Climax
http://www.highknoblandform.com/2009/10/high-knob-massif-reaches-glorious-color.html ].

Despite light, southerly winds across the summit area of High Knob, air became very cold within the depths of the Big Cherry, as rapid temperature drops amid the very dry air occurred beneath the exposed crestlines into the predawn hours of October 21.

Dry air is actually more dense than moist air, which meant that the air lying above Powell Valley was naturally more dense than the air in the Valley far below, even before any radiational cooling occurred within the Big Cherry.

The steep gradient of South Fork Gorge, which features an American Whitewater rated Class V+ extreme creek that plunges 1433 vertical feet in 4 miles ( 1391 feet of vertical drop occurring within 3 miles ), only acted to enhance the drainage of this dense air from the Big Cherry via downslope funneling and gravity.

[ Reference this American Whitewater Page for South Fork Gorge Whitewater details:
  http://www.americanwhitewater.org/content/River_detail_id_1992_.mobile ].

As cold air drained downward through awesome depths of South Fork Gorge it began undercutting, lifting, and cooling relatively warmer air below, such that condensation occurred and visible fog formed to spill outward across a frosty ground.

Frost formation out across the open Valley being largely a product of calm winds, radiational cooling, and down valley drainage of air cooling from the Valley head.

The depth of the coldest air in the first photograph by Roddy, at the beginning of this section, being denoted by the smooth, even top of the thick fog layer ( marking a notable low-level inversion ).

I write about this since the Cracker Neck of Powell Valley is simply notorious for nocturnal fog formations, and notable night-time drainage winds that blow through South Fork Gorge into the Valley opening.

[ South Fork Gorge can also alter orographic gravity waves, in the reverse direction, as air is funneled upward through the great Gorge from the northwest.  Indications of it's location have been well documented on NASA visible satellite images, via gravity wave breaks, all the way into northern Tennessee ].

A modifying factor in the above described processes being the 106 acre Big Cherry Lake, which adds both moisture to the overlying air ( at least a little ) and a little warmth, as air naturally drains across it's surface from the upper basin toward Big Cherry Dam and the head of South Fork Gorge.

[ Another modifying factor into the Valley being the forcing of fog formation, where the latent heat of condensation, that occurs upon development of fog, works to offset some of the cooling ].

Once the highcountry lake freezes over, as the Big Cherry can rapidly do following the onset of cold weather, all bets are off as the colder air of the highcountry basin can then filter down into the Cracker Neck ( without modification ) to drop temps lower than they would otherwise get on nights favorable for good drainage.

Throughout the year, tastes of the highcountry are transported down to the valley floors by cold air drainage corridors like this notable South Fork Gorge funnel.

This makes true heat waves a most rare phenomenon for valleys adjacent to the High Knob highcountry, as even if daylight hours are blazingly hot it is almost certain that nights will feature very significant temperature drops and refreshing breezes via the orographically driven climatic gradients of these drainage corridors ( e.g., it would be extremely rare to ever have a night stay above 70 degrees, as verified by NWS cooperative stations amid cool air drainages in the surrounding area ).

From East Stone Gap, the nature of the stair-stepping mountain terrain surrounding South Fork Gorge ( and its impressive drainage corridor ) is only partially visible.

[ Air draining the High Knob highcountry can develop rather impressive drainage flows, with many evenings at Legion Park, within the city of Norton, featuring flows which are strong enough to stretch out Old Glory ( our beloved American Flag ) as air drains off the northern slopes of the massif ].

From far away, as viewed from famous Powell Valley Overlook, the nature of these rugged, stair-stepping mountain ridges can be observed in this scenic photograph by Harold Jerrell.

Powell Valley Overlook of the High Knob Massif
Photograph by Harold Jerrell - © All Rights Reserved.

A dramatic landscape....a dramatic gradient in weather conditions, even amid what most think are "quiet" times!

[ Note that the beautiful stair-stepping mountain ridges, which become increasingly high with distance above the Valley floor, are located just southwest of the opening of South Fork Gorge ].

These dramatic weather gradients encompass all aspects of the local climate within this area, with 2009 precipitation totals as of mid-October varying from just over 53.00" at South Fork Gorge ( Big Stone Gap ) Water Plant, in Cracker Neck, to around 65.00" at Big Cherry Dam.

In reality, however, the Big Cherry Dam total is closer to 68.00" since hand measurements are not taken daily, like they are at the Water Plant ( the result being approximately 3.00" of loss from the rain gauge due to evaporation in between measurements ).

All measurements courtesy of Superintendent Gary Hampton, and his fine staff, of the Big Stone Gap WP.

Sunday, October 18, 2009

High Knob Massif Dazzles In First Wintry Blast


Elevation 4223 feet
High Knob Peak In Dazzling White - October 18, 2009
Photograph by Roddy Addington - © All Rights Reserved.

The High Knob Landform

The first snow & rime event of the 2009-10 winter season coated the High Knob Massif in a dazzling array of whiteness during the weekend of October 17-18.

A little light snow and rime coated the highcountry into early on October 17 as temps at the highest elevations fell into the 20s, with wind chill factors in bitter feeling 10s!

That mini-prelude mostly melted away during the daylight hours of Saturday, amid low clouds and fog, with the main event taking shape into the early hours of October 18.

While snowfall totals were generally 1" or less during the episode, riming was significant and absolutely gorgeous as captured beautifully by talented photographer Roddy Addington.

[ New reports into October 19 indicated that local snow depths reached 2" or more along some windward facing slopes, but otherwise were 0.5" to 1" or less within the area.  Some intervals of large snowflakes were reported down into the Wise Plateau, with no accumulation.  A little mixed sleet and flakes also fell with light rain and drizzle down to around the elevation of Clintwood ].

October 18, 2009
RIME Coated Northern Slope of High Knob Massif
Photograph by Roddy Addington - © All Rights Reserved. 

RIME makes the sprawling highcountry expanse of High Knob a water capturing wonder during the cold season, as moist, bitter winds are lifted and forced to rise, cool, and condense out their loads of moisture across its many lofty ridges & basins.

Although I have observed and studied RIME for many years, it NEVER fails to STUN and simply AMAZE me in the forms it can take as desposition occurs on trees and vegetation across the great expanse of the High Knob Massif.

This is why TREES are so important to the numerous lakes and wetlands amid this remnant massif of highcountry.  Along with fog drip during much of the year, trees generate and enhance secondary moisture sources which simply would not exist without them.  This makes the sprawling High Knob Massif a true water capturing wonder!

The above processes being vital to ALL LIFE within and downstream of the High Knob Massif ( including YOU )
in the Upper Tennessee River Basin.

Exotic Northern Red Oak RIME ( Quercus rubra var. borealis )
Photograph by Roddy Addington -© All Rights Reserved.

Is that a WOW photograph by Roddy, or what?

Simply wondrous are the ways of often moody Mother Nature when sub-freezing air, moisture, and high mountains get all tangled up. 

AMAZING!

Golden Rod ( Solidago spp. ) Coated With RIME on High Knob
Photograph by Roddy Addington - © All Rights Reserved. 

Mere written words, as I write this now, can not even begin to truly describe how magnificent this aspect is to the High Knob Landform.

Remember...
The High Knob Landform ( HKL ) is:

A great continuous mountain landform consisting of

1 ). a remnant massif of highcountry
( the High Knob Massif ) 

2 ). a northwestern mountain flank
( Little Stone-Stone-Cumberland mountains ) 

3 ). a southeastern mountain flank
( Powell Mountain-Newman Ridge ) 

4 ). an eroded calcareous core that separates these mountain flanks and narrows by headward erosion, to the northeast, into the inverted V-shaped Powell Valley ( adjacent to High Knob peak ).

October 18, 2009
Delicate Rimed Umbel on High Knob Massif
Photograph by Roddy Addington - © All Rights Reserved. 

The main rime zone within the remnant massif of High Knob extends from Cliff Mountain and Bowling Knob, the highest peak in Lee County, northeast along the Powell Mountain block to Thunderstruck Knob and Little Mountain ( i.e., along either side of the rugged Wise-Scott border ).

It then extends across lofty Big Cherry Basin & the High-Eagle Crest Zone ( High Knob & Eagle Knob peaks, highest points in Wise County ) to Camp Rock Knob ( highest peak in Scott County ) and the lovely Bowman Mountain ( within upper Clear Creek Basin of Wise County ). 

RIME can occasionally form much lower in elevation and nearly reach the valley floors, along northern & eastern slopes of the sprawling massif, during ideal situations with abundant moisture and very cold air enhanced by orographics.

Southwest of the remnant highcountry of the High Knob Massif the main rime zone caps the rugged northwestern flank of it's great High Knob Landform ( HKL ) to emerge with vigor once more across the lofty backbone of Cumberland-Brush mountains in majestic Cumberland Gap National Historical Park. 

Perhaps, that is one way famous 
"White Rocks" got their name?  

Northwestern Flank of The High Knob Landform
White Rocks of Cumberland Gap National Historical Park
Photograph by Harold Jerrell - © All Rights Reserved. 

The above described rime zones form during more typical NW-N air flow events, such as that which is currently being documented here for you to see with your eyes ( i.e., from October 17-18, 2009 ).

Reference the following section for more stunning examples


The High Knob Landform is, however, anything but typical, as orographically forced upslope flow on moist, southwesterly winds, or south to southeasterly winds, can bring the rime formation zone down into the windward facing slopes of these prevailing winds.

I explained the nature of rime
in a former newspaper article:

"On dark, cold winter days when cloud bases hang low across the great High Knob mass there is magic in the air.

Literally!

For when the clouds part, and sunshine returns, it is as if the Lord himself had taken a great brush and spread a blazing white blanket of sparkling crystals across the highcountry.

Visitors are simply amazed.

The substance which paints these gorgeous scenes is called rime, and while it may take different forms it is essentially frozen clouds of water!

While rime may cap any of the taller mountains of the southern Appalachians, it is special on High Knob.  For you see, High Knob is no ordinary mountain!

Unlike most southern Appalachian mountains which rise to a peak, then drop off the other side, the crest of High Knob spreads outward for mile, after mile, after mile.

Residents of Wise, Scott, and Lee counties have looked upwards all their lives at the beautiful white trees which stand like polished jewels against the dark blue of a winter sky."

For a perfect visual example of this please reference:


High Knob Massif - October 18, 2009
Trees Bow On Highcountry Route 619
Photograph by Roddy Addington - © All Rights Reserved.

One aspect that made this event extra special was some lingering leaves on the trees.

Although most leaves had fallen across the highest elevations ( thankfully, to reduce damage ), enough remained to create many glorious scenes!

October 18, 2009
High Knob Massif
Sugar Maple ( Acer saccharum var. saccharum )
 Photograph by Roddy Addington - © All Rights Reserved.

One of many incredible things about rime is that it GROWS INTO the moisture bearing winds.

In other words, RIME forms toward the north, headward, into a north to south blowing wind such as that which occurred into the morning hours of October 18 ( in 2009 ).

High Knob Massif
RIME on WINDWARD side of Branches
 Photograph by Roddy Addington - © All Rights Reserved.

This is beautifully illustrated by Roddy's photograph above, as ALL the rime has formed on the windward side of the tree limbs.  Essentially no rime has formed on the lee side, or downwind side, of the branches.

Is that not just the most AMAZING thing!

Even more impressive is that rime growth actually accelerates, or increases, as the wind speed increases.

Jefferson National Forest
Wind Swept High Knob Meadow - 4223 Feet
Photograph by Roddy Addington - © All Rights Reserved.

Strong winds can sweep the ground clean of snow, but rime deposition and growth can actually continue and increase with ROARING winds 
( as noted above ).

That is the single aspect, if nothing else, which clearly separates RIME from SNOW on trees, as a good wind gust will typically ( and often easily ) blow snow OFF tree limbs.

Exotic RIME Figure on High Knob - October 18, 2009
Photograph by Roddy Addington - © All Rights Reserved.

Let's look at that figurine a little closer!

Exotic Figurine Formed In Rime
Photograph by Roddy Addington - © All Rights Reserved.

You can find the most incredible, often unbelievable, features during rime events.  This is an AWESOME part of our mountain landscape, as exemplified by Roddy's next photograph.

WOW!

Stunning Northern Red Oak ( Quercus rubra var. borealis )
Photograph by Roddy Addington - © All Rights Reserved.

What excites me perhaps most of all about RIME is the amount of water it can add to the budget of an already wet location like that of the sprawling High Knob Massif.

RIME is a MAJOR secondary moisture addition, along with FOG drip in non-freezing air, to the annual water budget of the High Knob Landform.

However, it ONLY captures this moisture, and extracts it from the AIR, on upright objects such as TREES and vegetation.

[ In areas devoid of trees much of the cloud vapor will blow across and never be extracted from the air. If trees did not cap the High Knob Massif a great amount of moisture would pass leeward of this highcountry and simply evaporate away with subsidence, or sinking, of the air flow and never be captured.  Incredible! ].

Trees make the High Knob Massif
a WATER CAPTURING WONDER!!!
( the above derserving to be stressed once more ). 

In this light, trees are vital to our water supplies, with BIG, mature trees ( due to their much larger surface area ) being amazing scavengers of moisture via rime deposition upon them during sub-freezing conditions and fog drip from them during above freezing weather.

[ The above statement having NO "environmental" agenda toward loggers or non-loggers, but simply being based upon the absolute and true scientific facts and reality of what is, as can be proven by ANYONE willing to test it as I will explain below ].

Rime deposition on trees adds to the annual water budget upon it's melting, of course, but more often than not the process is a bit more complicated than just melting.

The following photograph by Roddy illustrates the true and ultimate importance of RIME.

RIME on ROAD - October 18, 2009
Photograph by Roddy Addington - © All Rights Reserved.

No, the importance is not that RIME can cover up a road.

The importance is that it can cover up a ROAD that has NO TREES directly above it, to illustrate how MUCH MORE it can cover the ground within woodlands BENEATH dense trees and vegetation!

Typically, on High Knob, rime falls off onto a snowpack.

Over time, and often with many multiple rime events, this ADDS a great amount of moisture to the snowpack, which then eventually melts to add water to our below ground water table, creeks, and water supply lakes.

A most amazing and little understood process by those not involved in it's study.

[ Although rime is more dense than hoar frost, and lighter than a glaze from freezing rain, it can accumulate enough at times to cause damage on High Knob.  INCHES of rime can sometimes build up during major or prolonged events, and even develop into long projections.

Long spears of rime have formed before on chain-link fences surrounding Tower sites in the Eagle Knob Communications Area on High Knob.  The most destructive situations develop when an ice storm, with freezing rain, is followed by riming which coats the ice to add additional weight ].

As I have written before,
ANYONE can prove to themselves the importance of RIME.

Get a 4" diameter National Weather Service rain gage, with inner measuring tube, and find a small bush to make it easier to manage.

SCRAP off ALL the rime on that bush into the rain gage.  Melt it down.  It will take very little math to realize how SIGNIFICANT this rime process is, given bushes collect only a tiny fraction of the rime of large trees.

For example, if the bush is 5 feet tall you will have to multiply your rain gage melted amount by a factor of 15 to represent a 75 foot tall tree and by a factor of 20 to represent a 100 foot tall tree ( but note, since bushes are so thin and low to the ground they typically will not collect as much rime as big trees which stand tall in the swirling air.  Your estimate will be low, perhaps, MUCH too low! ).

After you do that, simply ( dare I say ) multiply the AMOUNT obtained by ALL trees, shrubs, and even tall weed stems within the RIME formation zone!!!

Needless to say, the only conclusion is that this process of RIME formation is of VAST importance to the great High Knob Massif, and to all mountains tall enough to stand amid the rime formation zone ( i.e., amid the clouds in sub-freezing air for extended periods of time ). 

However, due to the unique base-to-base WIDTH of the High Knob Massif, it is especially important to the High Knob Landform!

Finally, I want to leave you with an original masterpiece by Mother Nature and my friend Roddy Addington. 

In this photograph it is actually possible to see where the colorful pigments of the Northern Red Oak have leached
into the RIME itself.  Absolutely stunning, and incredible!

High Knob Massif - October 18, 2009
Rime Swirled Northern Red Oak ( Quercus rubra var. borealis )
Photograph by Roddy Addington - © All Rights Reserved.

Need anyone say more!

Well, maybe just a few more words....
This is for those interested in how the above formed.
Air literally swirled around the Oak leaf seen in the foreground, as indicated by the SWIRL in the rime pattern.  This was caused by a micro boundary layer effect, much like occurs on a larger-scale within the friction layer of earth ( the famous Ekman Spiral for those familiar with mathematics and terrestrial-oceanic boundary layers
of planet Earth ).

The slightly concave nature of the leaf surface likely caused this to develop, with air swirling downward toward it's lower central section.

In this case, the trace of the air flow left an amazing swirl of frozen cloud vapor called RIME.