Saturday, March 24, 2018

Turbulent Weather Pattern Of Spring 2018


March 23, 2018
High Crest Lines of High Knob Massif
Snow Drifts In Wake of March 20-22 Storm
Photograph by Wayne Browning - © All Rights Reserved

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The first month of Meteorological Spring 2018 
has been turbulent, with all forms of precipitation including snow and ice storms in the high country of the High Knob Massif.

Afternoon of March 23, 2018
Kyle Hill & Kendall Morse In Snow Drifts
UVA-Wise Undergraduate Field Research
Photograph by Wayne Browning - © All Rights Reserved

Field research students Kendall Morse and Kyle Hill experienced interesting and beautiful high country conditions during March 23, as part of 
the expanding Undergraduate Research Program 
at the University Of Virginia's College At Wise.

March 23, 2018
High Knob Lake Dam
Looking Somewhat Like A Glacial Lake
Photograph by Wayne Browning - © All Rights Reserved


This included taking a snow core, surveying large snow drifts along high crest lines, as well as a hike into beautiful High Knob Lake basin where the lake was exceptionally beautiful with a wondrous aqua-green to bluish-green coloration.

March 23, 2018
Overflow At High Knob Lake Dam
Head of Mountain Fork of Big Stony Creek
Photograph by Wayne Browning - © All Rights Reserved

While steep southern exposed slopes around the lake had only patchy snow, a general 1" to 9" of snow depth remained on the northern exposed slopes.

March 23, 2018
Upper End of High Knob Lake
High Knob Lake Recreation Area
Photograph by Wayne Browning - © All Rights Reserved

A snow core generated 0.68" of water content to suggest at least 7" fell, if not a bit more given that snow density in these upper elevations had a snow-to-water ratio somewhat greater than 10:1 . 

*Most of the snow fell with air temperatures in the 10s to low-mid 20s.

March 23, 2018
Remote Section Of High Knob Lake
Photograph by Wayne Browning - © All Rights Reserved

Only part of the March 20-22 storm was snow, with a total water equivalent of around 2.00" or more in these upper elevations ( 1.28" measured at the base in the City of Norton ).

This continued a very wet pattern that had the 2018 precip tally up to approximately 25.00" at 
Big Cherry Lake Dam in advance of the nasty, water loaded snow-ice storm of March 24-25.

March 25, 2018
In Wake Of Ice-Snow Storm
Eagle Knob of High Knob Massif

Big Cherry Dam of High Knob Massif
 January-March Precipitation Totals

January 2018
5.48"

February 2018
14.37"

March 2018
7.09"

Total: 26.94"

A total of 30.82" of precipitation 
during the December-March period.

*The total is somewhat low due to wind induced rain gauge under-catch with air flowing across Big Cherry Dam ( rain gauges are 20 feet above the water level to the northeast and around 100 feet above ground level toward the southwest ).

March 31, 2018
Water Elevation 3120 feet
Big Cherry Lake of High Knob Massif
Photograph by Wayne Browning - © All Rights Reserved

March 31, 2018
Big Cherry Lake of High Knob Massif
Photograph by Wayne Browning - © All Rights Reserved

March 31, 2018
Big Cherry Lake of High Knob Massif
Photograph by Wayne Browning - © All Rights Reserved

Recent low temperatures in Big Cherry Lake basin dropped into the low-mid 10s during March 22 and into the low-mid 20s on March 31 ( the last 0 degree temperatures occurred in early February ).

Another morning featuring 10s in high country valleys is upcoming into April 5.


Historic Snowstorm
April 2-5, 1987

Spring snow is common in the mountains, with historic events occasionally occurring as mT 
( maritime tropical ) and cP ( continental Polar ) 
air masses clash.

A historic late season winter storm generated a general 2 to 4 feet of snow depth in locations along and north of the High Knob Massif during the first days of April in 1987.

Click through the charts to observe
the different isobaric levels in motion.

Reanalysis Charts
April 2, 1987 at 1200 UTC

Reanalysis Charts
April 3, 1987 at 0000 UTC

Reanalysis Charts
April 3, 1987 at 1200 UTC

Reanalysis Charts
April 4, 1987 at 0000 UTC

Reanalysis Charts
April 4, 1987 at 1200 UTC

Reanalysis Charts
April 5, 1987 at 0000 UTC

Reanalysis Charts
April 5, 1987 at 1200 UTC

Reanalysis Charts
April 6, 1987 at 0000 UTC

Reanalysis Charts
April 6, 1987 at 1200 UTC

Carl Henderson, electrical engineer for the former Blue Ridge PBS transmitter station on Eagle Knob of the High Knob Massif, reported a general 2 to 6 feet of snow depth in wake of this major event.

Total snowfall was generally significantly more than total snow depths due to settlement, melting and sublimation amid higher spring solar angles than indicated below ( the exception being much higher drifts which locally formed along mountain ridges ).

Nearly 2000 vertical feet below, Gary Hampton reported 3 feet of snow depth at the City of Norton Water Plant on the northern base of the High Knob Massif.  These were the greatest depths reported in Virginia during this event.

U.S.G.S. Digital Elevation Model

Great storm events tend to accentuate the great orographic sections of the Appalachians, with this epic April 1987 snowstorm being no exception.

Snow Depth Differentials

*High Knob Massif-Kingsport
48" - 11" = 36"

**Pickens-Millgap
42" - 10" = 32"

*A total of 14.8" officially measured at TRI in northeastern Tennessee which, like Kingsport, was downstream of the High Knob Massif & Cumberland Front during much of 
this storm event.

**Difference between Pickens, Wv., and Millgap in Highland County, Va., which was downstream of the Allegheny Front during much of this event.  A total of 32.8" of snow was measured at Snowshoe Mountain.

Bigger events in the past have generated even larger differences along storm flow trajectories, of course, with this being a nice mid-spring example.


Slow Emergence In 2018

April 1, 2018
Lower Elevations of Cumberlands
Rue Anemone ( Thalictrum thalictroides )
Photograph by Wayne Browning - © All Rights Reserved

The first Rue Anemones began blooming in lower elevations of South Fork Gorge of the Powell River by the end of February-early March, in wake of record February wetness and unseasonable mildness during mid-late month.  Numerous snowy periods and cold followed in March.

A colder, more snowy March than February in 2018 has emergence of spring ephemeral wildflowers off to a slow start, at least within locations along and north of the High Knob Massif.

April 5, 2018
Lower Elevations of Cumberlands
Bloodroot ( Sanguinaria canadensis )
Photograph by Wayne Browning - © All Rights Reserved

Big Cherry Valley 4 in the high country of the 
High Knob Massif shows the 2018 temperature trend well, with not only colder average temps during March than February but also average nightly low temperatures which have been 
colder in the first half of April than the average February minimum!

High Knob Massif
Big Cherry Valley 4 - Elevation 3186 feet
Average Temperatures January 1-April 14

Coldest Recent MINS

February 3
0 degrees

March 15
12 degrees

April 8
19 degrees

April 14, 2018
Field Research Students
Kyle Hill, Kendall Morse, Michael Hinkle
University Of Virginia's College At Wise

Some signs of spring are finally beginning to emerge in the high country, with Halberd-leaved Yellow Violets ( Viola hastata ) in bloom along with the first Dwarf Anemones ( Anemone quinquefolia var. minima ).  A vast array of Canada Mayflower 
( Maianthemum canadense ) is coming up but not yet blooming.  

April 14, 2018
Big Cherry Lake Wetland Valleys
Dwarf Anemone ( Anemone quinquefolia var. minima )
Photograph by Wayne Browning - © All Rights Reserved

April 14, 2018
Beaver Dam & Pond In Big Cherry Wetlands
Photograph by Wayne Browning - © All Rights Reserved

Beaver Dams in the valleys were breached by February floods, with upcoming maintenance 
work to be done by beaver colonies into 
the summer season.

February 2018 - Wettest On Record In Virginia

April 14, 2018
Sphagnum Filled Wetlands
Photograph by Wayne Browning - © All Rights Reserved

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