Monday, April 29, 2019

Spring 2019_High Knob Massif Area


April 27, 2019
Spring At Middle-Lower Elevations
View Below Flag Rock Recreation Area
Photograph by Wayne Browning - © All Rights Reserved

Spring conditions are now progressing rapidly at middle to lower elevations, below 3000 feet, to contrast with a continued early Spring state at upper elevations in the High Knob Massif.

April 27, 2019
Early Spring In Upper Elevations
View Above Flag Rock Recreation Area
Photograph by Wayne Browning - © All Rights Reserved

The first Bioblitz ever held in the Flag Rock Recreation Area was amid early spring conditions on April 27, with many species just emerging from their winter slumber.

April 27, 2109
Water Elevation 3318 Feet
Benges Basin of the Upper Tennessee River
Upper Norton Reservoir of High Knob Massif
Photograph by Wayne Browning - © All Rights Reserved

April 1-28, 2019
City of Norton Water Plant
Daily Hand-Measured Precip
( 9:00 AM / 24-Hour Daily)

04/05    0.38

04/07    0.04
04/08    0.02
04/09    1.03

04/13    0.19

04/15    0.63

04/17    0.01

04/19    0.95
04/20    1.65
04/21    0.16
04/22    0.01

04/26    0.55
04/27    0.25
04/28    0.03

April Total: 5.90″

2019 Total: 28.04″

12-Month Total: 80.09″

16-Month Total: 104.73

An abundant flow of water into high elevation lakes was observed on April 27, as more wind driven rain showers developed prior to sunset.

This was no surprise, of course, given the past year has produced 80" to 100"+ of total precipitation within the High Knob Massif area (80.09" at the base in the City of Norton).

April 27, 2109
Water Elevation 3318 Feet
Benges Basin of the Upper Tennessee River
Upper Norton Reservoir of High Knob Massif
Photograph by Wayne Browning - © All Rights Reserved

The dual Norton reservoir system is nearly 1000 vertical feet lower than the summit level of the High Knob Massif, nestled within Benges Basin.

April 27, 2109
Water Elevation 3230 Feet
Benges Basin of the Upper Tennessee River
Lower Norton Reservoir of High Knob Massif
Photograph by Wayne Browning - © All Rights Reserved

Although several hundred vertical feet lower 
than High Knob Lake, all these high valley lakes experience conditions featuring later spring and earlier autumn arrival times than adjacent middle to lower elevations (below 2700 feet).

While this is partly due to elevation, it is really driven by micro-climatic factors created by geology and topography.  Nocturnal cold air drainage rules high valley basins embedded within the sprawling top of the High Knob Massif, along with lifting of air across the high country, throughout all seasons of the year.

April 27, 2019
Flag Rock Recreation Area BioBlitz 2019
Upper Norton Reservoir of High Knob Massif
Photograph by Wayne Browning - © All Rights Reserved
(Left-right: Wayne Browning, Dylan Richardson & Mollie, Kendall Morse)

We found 30 species of birds during the late afternoon, which added to a few different birds observed earlier in the day by Dave Skinner and others, including a Bald Eagle, to make more than 3 dozen total species.  Not bad given numerous species are not yet on territory at upper elevations, plus significant water noise and late afternoon-early evening rain showers may have limited activity and detection. 

April 27, 2019
Flag Rock Recreation Area_City of Norton
Looking Toward Little Stone Mountain Gap
Photograph by Wayne Browning - © All Rights Reserved

Given current wetness it will be interesting to see how hot Summer 2019 gets, with June-August max temperatures at High Knob Lake reaching 80 degrees in 2017 and 81 degrees during 2018.

*Max summer temperatures reached 78 degrees in 2017 and 79 degrees in 2018 within the more sheltered valley location at the head of Big Cherry Lake basin (3200 feet elevation).

This compares to June-August max temperature readings of 77 degrees in 2017 on Eagle Knob and 2018 on the peak of High Knob (76.8 degrees).

March 27, 2019
Water Elevation 3500 feet
Majestic Cove At High Knob Lake
High Knob Lake Recreation Area
Photograph by Wayne Browning - © All Rights Reserved

The naturally moist environments of these wetland settings feed abundant summer cloud formations and frequent rains, in most years, to keep temperatures lower than would otherwise be expected from latitude and elevation alone.

March 27, 2019
Sun Reflection In High Knob Lake
Photograph by Wayne Browning - © All Rights Reserved

This plays a huge role in enhancing biodiversity, especially when combined with the unique geology and topography of this area, allowing many species with northern affinities to successfully live and breed here during summer.

April 21, 2019
UVA-Wise Field Trip
Undergraduate Kendall Morse
Photograph by Lynda Hubbard - © All Rights Reserved

This increases the importance of upper elevations and the need to protect and conserve these habitats which function as a buffer against the changing Holocene climate.

March 27, 2019
Water Elevation 3500 feet
High Knob Lake Recreation Area
Photograph by Wayne Browning - © All Rights Reserved

High Knob is a great sedimentary massif that rises on the Appalachian structural front as a tectonic mountain formed during the Alleghanian Orogeny, featuring a duplex-imbricate structure and karstic core that contains the deepest cave systems known east of the Mississippi in North America.

April 21, 2019
Looking To The Appalachian Structural Front
View From Ravens Next Peak Of Pine Mountain
Photograph by Wayne Browning - © All Rights Reserved

The Grenville Orogeny laid the basement foundation and a major Mid-Ordovician unconformity marked the beginning of 13 third-order tectophases that would fill and overfill the Appalachian foreland basin, setting the stage for stratigraphic rearrangement that followed during the Alleghanian which reached a climax during Absaroka II (Sloss subsequence) with closing of 
the Rheic Ocean and formation of Pangaea.

Coal bearing rocks that formed adjacent to the High Knob Massif and structural front created a layered plateau, whose erosion, later rejuvenation and incision is visible today as nearly even-topped ridges separated by dendritic hollows to contrast with the higher, asymmetrically folded, northwest verging, massif of High Knob.

An amazing geologic history recorded in the rocks and weathered sands of this ancient mountain landscape.

April 21, 2019
High Knob Massif Rises Above The Coalfields
Looking Across Pound To High Knob Along Horizon
Photograph by Wayne Browning - © All Rights Reserved

Pine Mountain stands as the northwestern-most tectonic mountain of the southern Appalachian fold-and-thrust belt.

This section is under construction.  Please check back.