Having high resolution and very accurate temperature data helps to illustrate why, since it certainly was not dryness in this area that triggered any early color changes ( perhaps a combination of cool temps and too much water on the wet-land valley floor that averages around 3200 feet ).
Any doubts about early color changes being a figment of imagination were quickly erased as September arrived, with unseasonable chill stimulating changes across the high country of the High Knob Massif.
Big Cherry Wetland 2 September 1-16 of 2017 Elevation 3248 feet
*A 9.0 degree average, per day, turn-around on Eagle Knob represented a huge change from the first half of September. This change was so great, in fact, that the average temp for the second half of September was the same as observed on Eagle Knob during the June-August period of summer!
By late in September early changing leaves at the highest elevations had either turned mostly brown or fallen as the focus of a new wave of color changes, with chill returning, shifted to northern slopes.
Big Cherry Wetland 2 September 2017 Elevation 3248 feet
A chilly start to October, with frosty cold conditions in high valleys and a general chill across the high country, brought significant color changes. Temps dropped to freezing and just below in the colder locations.
Majestic maples, ashes, birches and many other species had accelerated color changes in the upper elevations.
Average low temperatures as cold as 34 degrees were recorded in the Big Cherry Wetland Valley during the October 1-5 period. Although nights remained chilly through most of the first half of October, days again warmed to well above average.
Big Cherry Wetland 2 October 1-13 of 2017 Elevation 3248 feet
Mean temperatures again went back to around 58 degrees during the October 1-13 period ( the same as in September ). This was 10.4 degrees cooler than down in the Tri-Cities, but still well above average for October ( a low of 45 degrees in the Big Cherry Valley on October 12 was 15 degrees cooler than in the Tri-Cities, but still way above average ).
Big Cherry Wetland 4 October 1-13 of 2017 Elevation 3186 feet
*Less than ideal radiational cooling, with shallow to at times partial decoupling at best, limited the low to 31.5 degrees at Big Cherry Wetland 4. Locally colder temps likely occurred. The growing season ended at 145 days.
Although color could still be found, many trees along the high valleys and along the high crest lines were becoming bare of leaves as of October 13 ( in wake of heavy rains ). Nearly all the rain this month, of course, fell with Nate.
October 1-10 Rainfall
*City of Norton WP 2.74″
Big Cherry Dam 3.60″
Robinson Knob 4.69″
*Precipitation total of 50.56″ during 2017. Upper Elevations in the High Knob Massif have had a general 55.00″ to 60.00″+ this year.
As of mid-October, the peak at lower-middle elevations north of the High Knob Massif was yet to come, with color along Pine Mountain developing.
Birch Knob of Pine Mountain, at 3149 feet elevation, is below many of the valley floors within the High Knob Massif, often making a big difference in conditions.
*Birch Knob is the highest peak in Dickenson County, Virginia. The above view is from the Adam Childress Family Farm along Rt. 611, with the actual peak of Birch Knob being to the right of this view. Pine Mountain is certainly on my list of favorite mountains!
Holly and Alder are among many wetland species that include an array of sedges, rushes, ferns ( many having now died back ) and distinctive trees such as Yellow Birch and Black Cherry.
It looks like you can almost reach up and touch the clouds on days when they form on upslope flow into the high country, as noted in this view above on SE flow ( that is, of course, when bases actually do not drop down to engulf the upper elevations ).
When you climb to the top of the Lookout Platform on Birch Knob it seems like you’re at the top of the world, but it is all about perspective as the area that is above 3000 feet along the entire 120 mile crest line of Pine Mountain is very small compared to the 50+ square miles that sit above 3000 feet in the High Knob Massif. Sitting on a sprawling crest, valleys in places like the High Knob Massif, Burkes Garden, and Canaan Valley are unique in being able to cool quickly.
Autumn is a good time of year to illustrate what I mean, with the contrast between the valley of Big Cherry Lake versus the Tri-Cities, in the Great Valley, shown here.
The temperature at Noon on October 3 was not hugely different, varying from 63 degrees in the Big Cherry Valley to 68 degrees in the Tri-Cities. PM MAXS reached 72 degrees in Big Cherry Valley and 82 degrees down in the Tri-Cities. By 1750 hours ( 5:50 PM ) the temp difference varied from 63 degrees in the Big Cherry Valley to 81 degrees in the Tri-Cities. By 1950 hours ( 7:50 PM ) a 22 degree temperature difference had developed ( 72 degrees at TRI versus 50 degrees in the Big Cherry Lake Valley ). This difference held until the 2150 hour ( 9:50 PM ) observations when a 20 degree variation was reported ( 45 versus 65 degrees ). By about the midnight hour this difference diminished to 12 degrees.
The focus of best color development clearly shifted into the gorges of the massif, and toward middle-lower elevations, by October 18 amid an array of frosty cold mornings which featured 20s in high valleys.
The average low temperature observed during the period of October 17-21 was 28.2 degrees at the Big Cherry Wetland 4 site, with a total of 39.2 hours below freezing this month.
Such a long below freezing period equaled to a hard freeze within colder portions of the high valleys in the High Knob high country.
Afternoon maximums reached the 60s in upper elevations of the High Knob high country during October 21, following morning lows that dipped into low-mid 30s within coldest places.
Although some color remained on October 21, many bare trees were observed along the high crest-lines and high valleys in the High Knob high country, with best color development presently occurring throughout middle elevations toward the City of Norton.
What color remained looked very beautiful in the upper elevations, amid increasingly bare trees above 3000 feet, during late afternoon hours of October 21.
Temperatures did not go below freezing at High Knob Lake until the morning of October 17, some 12 days later than in Big Cherry Lake basin. This brings up an important point to be made. Regardless of whether a recording site is on an AM to AM recording format, or Midnight-Midnight format, too much emphasis is placed upon 2 single points in time ( i.e., the daily MAX and MIN which generate monthly and longer term climatological means ). What is truly most important, once you begin to understand the climate regimes of these places, is knowing WHAT the temperature is doing during all those other points in time + those two recorded values.
Air temps at 7:00 AM on the morning of October 18 varied from a relatively mild 53 degrees on Eagle Knob of the High Knob Massif to 34 degrees at High Knob Lake. At the same time, a temperature of 28 degrees was recorded at Big Cherry Wetland Valley 4 ( a 25 degree temperature difference in 1002 feet of vertical change ). This large difference was not restricted to a single point, the MIN recorded at 7:00 AM, but instead existed through extended time.
That is courtesy of decoupling, cold air drainage, and nocturnal temp inversion amid complex terrain. Differences of 30 degrees or more can occur at times ( nocturnal inversions of a few degrees to 10 degrees is more typical of rolling, lower elevation terrain ).
Lingering color from Flag Rock Recreation Area downward toward the City of Norton would set the stage for a mix of autumn-winter beauty as the first accumulating snow of this season fell during October 29.
This set the stage for the coldest temperatures of autumn with readings dropping down to around 20 degrees in the coldest high valleys in the high country.