The High Knob Landform

21 February 2025

Deep Snow and Rime

Eagle Knob of High Knob Massif

February 2025 has been wicked!

Everything from ice and snow storms to thunderstorms, high winds, and significant, damaging flash flooding and river flooding.

A general 11.00" to 12.00" of total precipitation have been hand-measured along the base of the High Knob Massif from the City of Norton to

Big Stone Gap, with up to 15.00" at the

summit-level of the massif.

What a month!

2 February 2025

Snow Drifts On High Knob Peak

The month started mild with a big rain event that continued to diminish the deep snowpack which developed during January.

2 February 2025

High Knob Massif

Snowy Head of High Knob Lake Basin

*Observe many downed trees from hurricane Helene

across the above view (much worse on other slopes).

A total of 3.13" of rain were measured at the

Big Stone Gap Water Plant in the South Fork of Powell River gorge during January 30-February 1, with locally 4.00" to 5.00" at upper elevations in the High Knob Massif.

2 February 2025

Northern Slope of High Knob Massif

This triggered high water and minor flooding, with the snowpack reduced to only northern slopes at highest elevations.

A few days of mild, dry conditions gave way

to a super-active pattern during February 5-21,

with one system after another pounding the

mountain landscape.

Significant Rainfall Event

(February 6-7, 2025)

Another significant rainfall event centered on February 6 developed in advance of the first

winter storm of the month.

Doppler Radar Rainfall Estimate

A general 2.00" to 3.00"+ of rain fell within

upslope locations of the High Knob Massif area.

This once again pushed creeks to high levels, with super-saturated conditions on the surface and within subterranean caves and conduits.

This event gave way to a notable cooling trend.

High-Country Rime Event

(February 9-10, 2025)

Low clouds banked against the western front range and foothills of the Appalachians during February 9-10 in advance of a developing winter storm (reference satellite images).

9 February 2025

High-Resolution Satellite Imagery

9 February 2025

High-Resolution Satellite Imagery

9 February 2025

High-Resolution Satellite Imagery

A significant rime event developed across

upper elevations of the High Knob Massif.

10 February 2025

High Knob Lookout

10 February 2025

High Knob Massif

Big Cherry Lake Basin In Background

This majestic array of rime added additional water to this already saturated (now freezing) mountain landscape.

10 February 2025

High Knob Massif

Looking Across Grindstone Ridge

Snow-Ice Storm

(February 11, 2025)

A total of 4" to 5" of dense snow gave way to a damaging ice storm across upper elevations of the High Knob Massif during February 11, with a general 0.3" to 0.5" of ice accumulation.

11 February 2025

Damaging Ice Storm

Along Route 238 on High Knob

This brought more trees down and knocked power out in the Eagle Knob Communications Complex.

11 February 2025

High Knob Massif

Ice Accumulation On Eagle Knob

11 February 2025

Elevation 4196 feet

Ice Accumulation On Eagle Knob

Significant Flood Event

(February 15-16, 2025)

Additional significant precipitation on following days reached a climax during February 15-16 with widespread flash flooding and river flooding.

January-February 2025

Daily Observations

City of Norton Water Plant

Data Courtesy of Andrew Greear & Staff

February 2025

Daily Observations

Big Stone Gap Water Plant

Data Courtesy of Gary Hampton & Staff

(Measured at the Big Stone Gap WP)

(From my Dickenson Star Weather Column)

"A general 3.00" to 6.00"+ of rain generated widespread flooding, with moderate to major flooding observed on the Russell Fork river at Haysi, portions of the Pound river, the Guest River at Coeburn, and lower reaches of the Clinch, Powell, Cumberland and Levisa Fork rivers.

More than 150 state roads were closed in Wise, Scott, Lee, Dickenson, and Buchanan counties by Saturday afternoon into early Sunday. Many structures and roads were damaged."

February 11-17, 2025

Precipitation Totals

The High Knob Massif was positioned along an

axis of heaviest rainfall during the week ending February 17, with the massif having the highest elevations into which SSW to SE air flow was

lifted (as detailed later, this was important).

The February 1-16 precipitation total reached 14.85" on Eagle Knob, more than 2200 vertical feet higher in elevation than the Big Stone Gap WP (*).

*This would be among the highest February totals ever documented in Virginia (14.37" at Big Cherry Lake Dam during February 2018 was the previous local record and all-time state record for Virginia).

February 2018 - Wettest On Record In Virginia

15 February 2025

South Fork of Powell River

**Overflow From Big Cherry Lake Dam

Video Courtesy of Gary Hampton

Despite having the dam spillway completely

closed, overflow from Big Cherry Lake basin

was tremendous by the afternoon hours

of Saturday (February 15, 2025).

**Communities such as Cracker Neck, East Stone Gap, and Big Stone Gap would have been in serious trouble if Big Cherry Dam had not been present to hold back a great amount of run-off (even though conditions were certainly bad enough, it would have been much more severe).

It amazes me how much water this landform can hold, with a combination of dams, wetlands, and subterranean conduits all being major factors for water retention (as noted later). Perhaps the most important factor is intact forests, which greatly reduce run-off versus logged-fragmented forests.

Mainstem River Levels

Headwater rivers draining the High Knob Landform and Cumberland Overthrust Block reached moderate-to-major flood levels.

Russell Fork of Big Sandy River

Pound River Above Indian Creek

Pound River Below Bold Camp Creek

Pound River At Norland (Dickenson County)

Guest River At Riverview (Coeburn)

Clinch River Near Speers Ferry

Clinch River Above Tazewell, TN

Powell River Near Jonesville

Powell River Near Arthur, TN

Cumberland River At Pineville, KY

Cumberland River At Williamsburg, KY

Levisa Fork At Pikeville, KY

Tributary Rivers-Streams

Flash flooding on tributary, headwater creeks and rivers reached minor-to-moderate levels across the mountain area (*).

*If the same amount of rain had fallen on the Russell Fork basin as fell across the High Knob Massif, flash flooding and river flooding would have been much more severe.

High Knob Massif dams at Bark Camp Lake,

Big Cherry Lake, High Knob Lake, City of Norton Reservoirs, Appalachia Lake and Rimrock Lake (northwestern arm) helped reduce direct run-off into headwater creeks and rivers.

Cranes Nest River Near Clintwood

The presence and benefit of middle-upper elevation wetlands, such as those in The Glades (Glady Fork of Big Stony Creek) and Wolf Creek (Laurel Fork of Stock Creek) should also not be discounted for their water retention abilities in these settings.

Big Stony Creek (Fort Blackmore)

Subterranean conduits, some associated with major

cave systems, also acted as sources of underground

water storage until they completely filled to overflow.

South Fork of Powell (Big Stone Gap)

A near fatal event was fortunately prevented

by the Bristol Swift Water Rescue Team when a vehicle was swept away by the North Fork of Clinch River near Duffield.

The occupant was found stranded on top

of the vehicle and rescued by the Team.

North Fork of Clinch River (Duffield)

Wallen Creek At Pennington Gap

The flood event ended with a general 1-2" of snow below 3000 feet, with 2-3" across upper elevations above 3000 feet.

17 February 2025

Eagle Knob of High Knob Massif

Winter Majesty In Wake Of Flood

17 February 2025

Winter Majesty In Wake Of Flood

Winter Storm & Bitter Air

(February 19-21, 2025)

The next winter storm came in two

phases during the February 19-21 period.

18 February 2025

Eagle Knob of High Knob Massif

A fast moving southern stream system dropped

a general 2-4" of snow during February 19.

19 February 2025

Eagle Knob of High Knob Massif

This was followed by an upper-level low and N-NW flow snowfall during February 20 into early hours of February 21.

20 February 2025

Eagle Knob of High Knob Massif

Storm snowfall totals reached 4" to 6" below 3000 feet, with 6" to 10" across the high-country above 3000 feet.

21 February 2025

Eagle Knob of High Knob Massif

Minimum temperatures dipped to near and below zero degrees at upper elevations, above 3000 feet, with widespread sub-zero wind chill factors.

21 February 2025

High Knob Massif

High Knob Lookout

21 February 2025

High Knob Massif

Snow-Rime Laden Northern Slopes

21 February 2025

High Knob Massif

Snow-Rime Laden Northern Slopes

Winter Precipitation Difference

(Incredible Contrast Across Mountain Empire)

An absolutely incredible difference has been observed during Winter 2024-25 between the

High Knob Massif area and the Great Valley of northeastern Tennessee.

Total Precipitation

(December 1-February 16-17)

City of Norton Water Plant: 21.95"

Big Stone Gap Water Plant: 22.15"

Eagle Knob of High Knob Massif: 29.23"

Air Mile Distance

Eagle Knob to Tri-City Airport

A total of 9.60" of precipitation have been officially measured at Tri-City Airport since the beginning of Meteorological Winter (1 December 2024).

(As of February 22, 2025)

NWS Precipitation Totals

Tri-City Airport, TN

This is not only much less than observed during February 1-16 in the City of Norton to Big Stone Gap corridor, it is incredibly less than the 29.23" reported on Eagle Knob since the start of Meteorological Winter (***).

***This includes missing data in frozen precipitation. Totals of 22.00" to 23.00" have been hand-measured along the base of the High Knob Massif (City of Norton and Big Stone Gap water plants) since the beginning of Meteorological Winter.

The difference in winter snowfall totals has been even more stunning, with 7.9" at Tri-City Airport versus 81.00" on Eagle Knob (despite only a 31.4-air mile difference between the two sites).

The elevation difference between Eagle Knob and

Tri-City Airport is 2677 feet (4196 versus 1519 feet).

The 2024-25 winter season is currently tied for the 12-snowiest of the past 32-winter seasons at lower elevations (below 2000 feet) northward of the High Knob Massif (where northerly air flows are forced to rise upward toward the high terrain).

Lower Elevations

Clintwood 1 W NWS (#)

(Snowfall In Inches)

#The elevation at Clintwood 1 W is approximately

the same as at Tri-City Airport in NE Tennessee.

Extreme precipitation differences continue when comparing the High Knob Massif area with the New River Valley, Roanoke Valley, and locations east of the mountains in the Virginia Piedmont.

NWS Precipitation Totals

NWSFO Blacksburg, Virginia

The notable difference here is that both the New River and Roanoke valleys are running well above their longer-term averages for precipitation, while Tri-City Airport has received below average precipitation.

NWS Precipitation Totals

City of Roanoke, Virginia

NWS Precipitation Totals

City of Danville, Virginia

These west-to-east precipitation differences across Virginia, and the Great Valley, are common. Many have been highlighted during the past 16-years.

Rewriting Virginia Climatology (2011)

Late Summer 2021_High Mountain Basins

February Air Flow Trajectory

(Mean Orographic Forcing)

What made February 2025 so very

wet in the High Knob Massif area?

Vector Wind

February 1-20, 2025

925 MB Composite Mean

Part of the reason is related to the mean air flow trajectory, with a SSW inflow into the High Knob Massif through the wide open expanse of the

Great Valley of eastern Tennessee.

Vector Wind

1948-2020 Mean (72-Year)

925 MB Annual Composite

February 2025 flow was analogous to the mean annual, long-term air flow trajectory at 925 MB (near elevation of Wise) which helps make the

High Knob Massif area the wettest in Virginia.

There is nothing downstream as

elevated as the High Knob Massif.

Air Flow Trajectory And Terrain

The mean-layer 850 mb-Surface vector anomaly was essentially identical to this flow, meaning that the bulk of heavier rainfall (in this case) was being forced to rise across the 3000-4000+ foot terrain of the massif with limited downstream moisture extraction in the lower atmosphere.

850 MB to Surface

February 1-20, 2025

Vector Wind Layer Composite Anomaly

The 925 MB vector wind composite anomaly was also favorable for efficient lifting and convergence along the massif from the southeast (and river valleys of the Clinch and Holston).

Vector Wind

February 1-20, 2025

925 MB Composite Anomaly