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PHYSICAL SETTING:

Climate

Vegetation

Geologic History

     Maps

    Bedrock 

     Glacial

      Landforms

Climate

The climate at the Hartnett Site is temperate continental (Dfb according to the Koppen classification system).  Climate date for Dunn county is supplied in the tables below. 

Definitions

Average Temperature is the monthly mean of the daily (24 hour) temperature.

Average Maximum Temperature is the monthly mean of the maximum daily temperature.  

Average Minimum Temperature is the monthly mean of the minimum daily temperature. 

In winter, the average temperature is 16.8 degrees F and the average daily minimum temperature is 6.7 degrees.  The lowest temperature on record, which occurred at Menomonie on February 3, 1996, was -40 degrees.  In summer, the average temperature is 69.7 degrees and the average daily maximum temperature is 82.4 degrees.  The highest temperature, which occurred at Menomonie on August 2, 1964, was 101 degrees.

Averages (Fahrenheit) 
  Jan Feb Mar Apr May Jun Jul. Aug. Sept. Oct. Nov. Dec.
Max 23.8 30.1 42.5 59.6 72.2 80.4 85.2 82.4 73.1 61.8 43.8 28
Min 2.6 7.5 20.8 33.9 45 54.4 59.5 57 48.6 37.9 25.2 10.2
Mean 13.2 18.8 31.7 46.8 58.6 67.4 72.4 69.7 60.9 49.9 34.5 19.1

Daily Extremes (Fahrenheit)

 

High

Date

Low

Date

January

55

24/1981

-39

09/1977

February

60

25/1976

-40

03/1996

March

82

29/1986

-34

01/1962

April

90

22/1980

5

04/1995

May

92

28/1969

20

03/1967

June

98

30/1963

30

01/1993

July

100

18/1964

41

04/1972

August

101

02/1964

37

14/1964

September

96

06/1978

25

29/1967

October

90

04/1997

12

30/1988

November

76

08/1999

-13

29/1985

December

64

01/1998

-36

19/1983

Precipitation

Definition: Average Rainfall is the mean monthly precipitation, including rain, snow, hail etc.

The average annual total precipitation is about 29.29 inches.  Of this, about 18.8 inches, or 64 percent, usually falls in May through September.  The growing season for most crops falls within this period.  The heaviest 1-day rainfall during the period of record was 4.72 inches at Menomonie on August 31, 1977.  Thunderstorms occur on about 37 days each year, and most occur between May and August.

Averages (inches)

 

Mean

High-Year

Min-Year

1-Day

January

0.82

4.02-1967

0.02-1981

1.14-25/1967

February

0.60

2.41-1951

0.00-1958

1.25-26/1951

March

1.56

6.01-1998

0.12-1960

1.86-28/1998

April

2.62

5.66-1968

0.26-1987

3.41-23/1968

May

3.30

8.12-1991

1.14-1966

2.47-10/1963

June

4.20

8.69-1990

1.52-1964

3.25-01/1965

July

3.69

10.22-1997

0.89-1998

3.79-08/1959

August

3.87

11.78-1975

1.21-1970

4.72-31/1977

September

3.75

8.41-1986

0.91-1969

2.87-26/1973

October

2.35

5.42-1970

0.43-1976

2.58-07/1992

November

1.48

7.28-1991

0.0-1976

3.41-01/1991

December

1.03

2.82-1969

0.14-1958

1.39-28/1959

Snow (inches): The average seasonal snowfall is 41.9 inches.  The greatest snow depth at any one time during the period of record was 40 inches recorded on February 5, 1971.  On an average, 98 days per year have at least 1 inch of snow on the ground.  The heaviest 1-day snowfall on record was 11.7 inches recorded on December 19, 1968.
Snowfall  
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Mean 11.5 7.4 8.4 1.6 0 0 0 0 0 0 3.7 0
High-Year 33.3-1967 19.4-1962 25.4-1965 9.8-1965 0-2000 0-2000  0-2000 0-2000 0-2000 4.8-1959 20.1-1991 34.1-1968
Number of Days Precipitation Exceeds Indicated Amounts
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
>.01 7.7 5.2 8.4 9.7 11 10.1 10.1 9.8 10.1 8.8 7.3 7.2
>.5 0.2 0.2 1 1.6 2.3 2.6 2.6 2.6 2.7 1.3 1 0.4
>1 0 0 0.3 0.5 0.7 1 1 1.1 0.8 0.4 0.2 0.1

Growing Degree Days

Date of Last Spring Occurrence     
Base Temp-F
Median
Early
90%
10%
Late
32
5/13
4/16
4/26
5/28
5/31
30
5/06
4/09
4/23
5/18
5/29
28
4/29
4/05
4/12
5/09
5/12
24
4/15
4/03
4/07
5/02
5/10
20
4/07
3/21
3/23
4/19
5/02
16
3/26
2/26
3/12
No Data
4/13

 Date of First Fall Occurrence 

Base Temp-F

Median

Early

10%

90%

Late

32

9/28

9/03

09/20

10/07

10/08

30

10/05

9/22

9/26

10/23

10/30

28

10/06

09/26

09/29

10/27

11/04

24

10/24

10/02

10/07

11/07

11/11

20

11/02

10/02

10/15

11/12

11/15

16

11/11

10/20

10/27

11/25

11/29

Growing Season: Based on the average length of growing season using three index temperatures at 10, 20, 50, 80, and 90% probabilities.

Daily Minimum Temperature During Growing Season 

Probability

>24

>28

>32

9 years in 10

165

147

119

8 years in 10

172

153

125

5 years in 10

187

165

138

2 years in 10

202

177

150

1 year in  10

210

183

157

Information regarding weather data was recorded for the period 1961-90 at : MENOMONIE SEWAGE PLANT, WI

Group #1


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Vegetation

Dunn County Vegetation

Dunn County vegetation in the 1830's consisted mostly of prairies and mixed conifer and deciduous forests which included:  Burr, White, Black, and Red oak; Sugar Maple; Basswood; White Cedar; Black Spruce; Tamarack; Hemlock; Jack, White, and Red Pine; Aspen; White and Yellow Birch.  Native vegetation of Dunn County was characterized by exceptional complexity and species richness.   Much of this biodiversity still exists today.  For a larger view of the map below click on this website:

http://www.dnr.state.wi.us/org/at/et/geo/map_gal/landcov/orgveg.htm

 

In 1965 Dunn County land cover consisted mainly of deciduous mixed forest (Aspen, Basswood, Bur Oak, Black Oak, Elm, Sugar Maple, and White Oak), prairie, and agricultural land.  A full Dunn County land cover map can be seen at: http://www.dnr.state.wi.us/org/at/et/geo/map_gal/landcov/lulc.htm

The Hartnett site (red dot) is located within the Southwestern Upland Natural Division.  Vegetation cover consists of Oak Savannahs, Deciduous hardwood forests, and Prairies. The Natural Division map can be viewed at:

http://www.dnr.state.wi.us/org/at/et/geo/map_gal/landcov/lulc.htm

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Geologic History

Precambrian and the Paleozoic rocks make up the bedrock of Wisconsin. Glacial deposits, which include clay, sand, and gravel, cover bedrock in the northern and eastern three-fifths of the state.  The southwestern part of the state, also called the Driftless Area is the only part of the state that was never glaciated.  In the Dunn County area, the bedrock is Cambrian sandstone with some dolomite and shale.  More specifically it is part of the Mt. Simon formation, a medium to coarse-grained quartz-rich sandstone.  In the Pleistocene period, glaciers entered the area from the north.  Large volumes of meltwater emanating from retreating glaciers at the end of the last glaciation, carved deep wide river valleys and deposited extensive sandy and gravelly deposits.  The Wissota Terrace, located along the margins of the Chippewa River valley, is one such deposit.

Group #4

Maps

Bedrock Map

 

 

 

 

 

 

Glacial Map

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Landforms Map