MIME-Version: 1.0 Content-Type: multipart/related; boundary="----=_NextPart_01C743C1.840D9420" This document is a Single File Web Page, also known as a Web Archive file. If you are seeing this message, your browser or editor doesn't support Web Archive files. Please download a browser that supports Web Archive, such as Microsoft Internet Explorer. ------=_NextPart_01C743C1.840D9420 Content-Location: file:///C:/CE9ABE10/GSMNP.htm Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="us-ascii" Great Smoky Mountain National Park

Great Smoky Mountain National Park

Snow= fall Analysis=

 <= /span>

by David Hotz=

 

 

1.   &n= bsp;  Introduction<= /o:p>

 

The Great Smoky Mountain National Park (GSMNP) is located across eastern Tennessee and western North = Carolina (Fig. 1) and contains some of the most diverse terrain in the eastern United States.  Elevations in the park range from = 875 to 6,643 feet (Fig. 2).  The Weat= her Forecast Office at Morristown, Tennessee has the responsibility for issuing forecasts for the Tennessee side of the park.  The GSMNP is one of the most visit= ed national parks in the United States with a variety of outside activit= ies, such as hiking, camping, fishing, and sightseeing. 

 

The main road across the park is U.S. highway 441, which crosses NewFound Gap at an elevation of 5048 feet MSL.  The purpose of this study is to ex= amine the differences in snowfall across the Great Smoky Mountain National Park, and to compare the average snowfall with the surrounding Automated Surface Observation Systems (ASOS) across eastern Tennessee and west= ern North Carolina.<= o:p>

 

2.   &n= bsp;  Data=

 

The study will compare 15 years snowfall data from five daily reporting stations across the Great Smoky Mountains.  The five stations are the following:  Park Headquarters (elevation 1600 feet MSL), Cades Cove (elevation 1900 feet MSL), Oconaluftee (elevation 2040 feet MSL), Newfound Gap (elevation 5048 feet MSL), and Mount LeConte (elevation 6400 feet MSL).  Th= ese stations report daily snowfall as of 7 am Local Standard Time (LST).  

 

Approximately ten years of snowfall data, which is between March 1991 and February 2001, = were obtained from the GSMNP archive.  The Weather Forecast Office at Morristown, Tennessee has archived data= from the GSMNP from 2001 to present.  The 15 years of data were entered into spreadsheet software in order to generat= e graphs of yearly, monthly, and daily snowfall comparisons between the stations.

 

Average snowfall for eastern Tennesse= e and western North Carolina ASOS sites were obtained from the National Clima= tic Data Centers (NCDC) Local Climatological Data.  The three ASOS sites are the following:  Knoxville McGhee Tyson Airport (elevation 981 feet MSL)= , Tri-City Regional Airport (1519 feet MSL), and Asheville, North Carolina Airport (2165 feet MSL).

 

 

 

 

3.   &n= bsp;  Yearly Snowfall

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The average yearly snowfall (Fig. 3) shows a large variation between the lower terrain stations, such as Park Headquarters, and the higher terrain station= s, such as NewFound Gap and = Mount LeConte.  The difference between Park Headqu= arters and Mount= LeConte is around 90 inches.   The lower terrain locations r= eceive an average yearly snowfall around 12 inches with Mount LeConte’s average is nearly 100 inches.

 

The average snowfall for the park’s lowest elevations stations, which are Park Headquarters and Cades Cove, is only about 2 inches more than the Knoxville Airport.

 

The large temperature difference between the lower and higher elevations is lik= ely a major reason for the enhanced average snowfall for NewFound Gap and Mount LeConte.  Gaffin, Hotz, and Getz (2002) conc= luded the differences between high temperatures were similar to the moist adiabat= ic lapse rate of 3.30F per 1000 ft between Park Headquarters and Ne= wFound Gap.  The upslope lift into the higher terrain is also a contributor. 

 

The yearly snowfall graph does illustrate a fairly significant difference betwe= en the two

higher elevation stations, NewFound Gap and Mount LeConte.  It is interesting that the differe= nce in yearly snowfall is nearly 35 inches with only a 1400 feet MSL change in elevation.  Research from Perr= y and Konrad et al. (2005) has found that northwest flow wind trajectories from t= he Great Lakes into the windward slopes of the eastern Tennessee mountains, su= ch as the Great Smoky Mountains, enhances snowfall.  A relief map (Fig. 4) shows that <= st1:PlaceType w:st=3D"on">Mount LeConte is in a very favored windward slope location to intercept the upslope moist= ure flowing from the Great Lakes.  The relief map also shows that New= Found Gap is likely shadowed by the mountains to the west and northwest.  The shadowing effect would block t= he deepest moisture from intercepting the windward slopes of NewFound Gap.

 

Mount LeConte average snowfall = over the last 15 years is nearly 100 inches, but a graph (Fig. 5) of yearly snow accumulation shows a wide range.  The minimum snowfall was less than 45 inches in 1991 with the greate= st accumulations reported in 2003 with over 160 inches.

 

Snowfall data (Table 1) shows several years when the lower elevations stations recei= ved an inch or less of snow accumulation for the entire year.  The least yearly snowfall was only= a trace at Cades Cove in 1992 and Oconaluftee in 2005.

 

The snowiest year for the entire park was 1993, which was the year of the Super= -Storm, with an overall average snowfall for the 5 stations being almost 75 inches.  The year with the lea= st snowfall was 1991 with a 5 station average of less than 20 inches.

 

The average number of days per year with snowfall of 1 inch or more varied from= 4 and 5 across the lower elevation stations to 26 at <= st1:PlaceType w:st=3D"on">Mount LeConte (Fig. 6).  The yearly number o= f days of snowfall at NewFound Gap is around 19, which is similar to the normal 18 snowfall days at Minneapolis Saint Paul, Minnesota.

 

4.  Monthly and Daily Snowfall

 

The monthly average snowfall shows a wide range between the ASOS sites, GSMNP l= ower elevation stations, and the park higher terrain stations (Table 2).  Overall, the snowiest month across= the park is January with the highest average monthly snowfall around 25 inches at Mount LeConte.  It is interesting to note that all= of the park stations showed a slight decrease in average snowfall for February compared to January and March (Fig. 7).&nb= sp;  The slight decrease co= uld be contributed to three less days in the month of February and the Super-Storm= of March 1993.

 

Only NewFound Gap and Mount LeConte reported sn= owfall in the months of May and October.  The earliest snowfall for NewFound Gap is October 25th, w= hich occurred in 2005, with 1.5 inches.  <= /span>  The earliest for Mount LeConte is October 19th, which occurred in 1996, with 0.1 inch.  The latest snowfall for both NewFo= und Gap and Mount LeConte occurred on May 8-9th= , 1992 with 4 and 12.5 inches, respectively.

 

The latest first snowfall in the park occurred in Winter of 2001-2002.  Mount LeConte did not receive its first measurable snow until December 24th, 2= 001 with only 0.5 inch.  NewFound Gap d= id not receive any measurable snow until January 7th, 2002.

 

The greatest number of days with snowfall of 1 inch or more is at the Mount LeConte station with an average of 7 days for the month of January (Fig. 8).  NewFound Gap’s greatest numb= er of days with snowfall of 1 inch or more is 4.9 for the month of January.  This number is comparable to the n= ormal number of days of snowfall for January at Minneapolis Saint Paul, Minnesota, which is 4.5.&n= bsp; The lower elevations stations, such as the Park Headquarters and Cad= es Cove, average between 1 and 1 ½ days of 1 inch or more of snowfall f= or January through March.   = This is comparable to both the Tri-City and Asheville Airports<= /st1:PlaceType>.

 

The greatest daily snowfall for each of the park stations was reported during t= he March 13-14th, 1993 Super-storm. Mount LeConte received over 30 inches on March 14th, 1993 (Fig. 9).=

 

4.   &n= bsp;  Conclusions

 

The GSMNP has its own unique climatology with average snowfall varying greatly across the park.  These variat= ions are mainly due to elevation differences, which secondarily affect temperatu= re, upslope and downslope flow, and the capture of Great Lakes moisture along the windward slopes.  It is crucial for the visitors of the GSMNP to have an understanding= of these wide variations in snowfall climatology across the park= ,  especially the difference i= n average snowfall between Park Headquarters and the higher elevation locations, such= as NewFound Gap and Mount LeConte.=

 

Visitors of the GSMNP can get a false sense of security by the usually limited snowf= all across the southern United = States, but then get caught off guard by the potential heavy snowfalls over the hig= her terrain.  Travelers and hikers= through the NewFound Gap should realize that the average snowfall is 62 inches, whi= ch is more than Boston, M= assachusetts with an average of 43.8 inches or Chicago, Illinois with an average of= 38 inches.  The number of days pe= r year with 1 inch of more of snowfall is also much greater at NewFound Gap with 19 days, then both Boston, Massachusetts and Chicago, Illinois which each average around 12 = days.

 

The snowfall climatology at Mount LeConte is similar to Caribou, Maine.  Both locations have an average annual snowfall around 100 inches with the average number of days per year with 1 inch or more of snow around 26 at Mount LeConte and 29 at Caribou, Maine.

 

Additional research on heavy snowfall pattern recognition for the GSMNP would be beneficial.  Also, as addition= al snowfall data is archived, a more complete snow climatology analysis of the park could be done.

 

 

Acknowledgements=

 

The author would like to thank Jack Ramsden and Clayton Brantley of the National Park Service for providing the GSMNP snowfall data used in this study.  Thanks to David Gaffin, Senior Fore= caster WFO Morristown, Ten= nessee, for both the map of east Tennessee and t= he topographic map of the Great Smoky Mountain National Park.  Also,

I would like to thank Jack Settelmaier, SSD, Southern Region Headquarters, = Fort Worth, Texas<= /st1:State> for reviewing the paper.

 

 

References

 <= /span>

            Gaffin, D.M., D.G= . Hotz, and T.I. Getz:  An Evaluation of Temperat= ure Variations around the Gre= at Smoky Mountains National Park and their Associated Synoptic Weather Patterns. NOAA Technical Memorandum (NWS SR-221).

 

        =     NOAA Satellite and Information Service, National Climatic Data Center,

U.S. Department of Com= merce: website: http://hurricane.ncdc.noaa.gov/cgi-bin/climaps/climaps.pl.

 <= /span>

        =     Perry, B and C.E. Konrad: The Influence of the Great Lakes on Snowfall Patterns

in the Southern Appalachians. Proceeding of the 62nd Eastern Snow Conference: 225-246. =

 <= /span>

 <= /span>

 <= /span>

 <= /span>

 <= /span>

 <= /span>

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<= /o:p>

Figure 1. Map of the Southern Appalachians.  The hatched area is the location of

GSMNP.  The three-letter ASOS identifiers denote the location of the Tri-City (TRI), Knoxville McGhee Tyson (TYS), and Asheville (AVL) airports.

 

<= /o:p>

 <= /span>

Figure 2. Topographic contour map= (feet MSL) of the GSMNP.    The bold line is the boundary of the park.

 <= /span>

 <= /span>

  Figure 3.  Average yearly snowfall for the GS= MNP stations and the eastern

  Tennessee ASOS.

 <= /span>

Figure 4.  A relief map of the Mount LeConte and NewFoun= d Gap areas of the GSMNP.

 <= /span>

   Figure 5.  Yearly snowfal= l for Mount LeConte from 1991 through 2005.

 

 

 <= /span>

 <= /span>

Table 1. Yearly Snowfall f= or the five park stations (1991-2005)

 

Park Headquarter= s

 

Cades Cove<= /o:p>

 

Oconaluftee=

NewFound Gap

Mount LeConte

1991

2.50

7.50

9.75

33.87

44.51

1992

1.00

0.00

1.00

50.25

89.00

1993

24.00

34.00

57.00

106.55

153.25

1994

7.75

10.75

2.25

45.25

64.35

1995

12.13

9.15

9.79

58.27

99.16

1996

29.84

36.29

29.96

90.03

113.79

1997

15.00

12.45

12.52

47.76

73.41

1998

15.70

5.75

4.25

77.75

140.35

1999

7.55

3.00

11.75

62.10

93.70

2000

9.00

8.05

17.70

45.60

64.50

2001

10.00

10.00

6.00

54.50

91.00

2002

6.20

5.50

6.00

43.50

72.00

2003

18.00

15.00

23.00

98.00

162.50

2004

5.00

10.00

3.50

88.50

124.50

2005

4.50

1.00

0.00

58.50

108.50

 <= /span>

 

 

 

 

 

  Figure 6.  The average nu= mber of days with snowfall of 1 inch or more per year.

 <= /span>

 <= /span>

 <= /span>

Table 2.  Monthly average snowfall (inches) for the GSMNP station and the east= ern Tennessee ASOS  <= /span>(1991-2005).

 

 

Knoxville Airport

Tri-City Airport

Park       &nbs= p;            Headquarters

Cades Cove

       &nbs= p;            &= nbsp;   Oconaluftee

Asheville Airport

NewFound Gap

Mount

LeConte

 

 

 

 

 

 

 

 

 

Jan

3.70

5.50

4.36

3.99

3.03

<= span style=3D'mso-spacerun:yes'>       &nbs= p; 4.30

17.99

25.28

Feb

3.00

4.10

2.13

1.90

1.90

<= span style=3D'mso-spacerun:yes'>       &nbs= p; 4.10

13.16

20.42

Mar

1.60

1.90

3.15

3.51

4.82

<= span style=3D'mso-spacerun:yes'>       &nbs= p; 3.10

15.57

24.80

Apr

0.80

0.90

0.40

0.13

0.00

<= span style=3D'mso-spacerun:yes'>       &nbs= p; 1.00

2.92

7.46

May

0.00

0.00

0.00

0.00

0.00

<= span style=3D'mso-spacerun:yes'>       &nbs= p; 0.00

0.27

0.83

Jun

0.00</