Colorado's Climate Colorado's Climate --Then and NowThen and Now
Nolan DoeskenNolan DoeskenColorado Climate CenterAtmospheric Science Department
Presented to Channel 7News, Colorado Climate Change Seminar, April 12, 2006, Denver, CO
Prepared by Odie Bliss with assistance of Wendy Ryan, Daniel Dennison, and Peter Rogers Photo by Lynn Kral
Perspectives on Colorado’s Climate
We have a lot of weather data!
Kirk, Colo, CSU CoAgMet weather
http://www.coagmet.com
April 2005-2006
Instrumental weather observations date back to the late 1800s
Las Animas Annual Precipitation(1867-2005)
0
5
10
15
20
2518
65
1875
1885
1895
1905
1915
1925
1935
1945
1955
1965
1975
1985
1995
2005
Prec
ipita
tion
(inch
es)
UTAH 1930
We are indebted to NWS for maintaining long-term weather stations
Army Signal Service (began 1870-1891)Weather Bureau (1890-1969) National Weather Service (1970-present)
Climate is variable
Colorado Average Annual Precipitation
Fort Collins Historic Weather Station –Continuous observations from 1889 to present
Fort Collins Yearly Precipitation
25.24
28.4327.57
7.917.347.857.13
0
5
10
15
20
25
30
1885
1890
1895
1900
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Year
ly P
reci
pita
tion
(inch
es)
Fort Collins Daily Accumulated Precipitation
0
5
10
15
20
25
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
Prec
ipita
tion
(inch
es) WY1999
WY2002
Average
A few storms contribute a large fraction of our precipitation
Fort Collins Daily Accumulated Precipitation for WY2003
0
5
10
15
20
25
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug SepPr
ecip
itatio
n (in
ches
)
Fort Collins Flood July 1997
Precipitation varies with the seasonsWater Year Average (1971-2000) Precipitation for Selected Stations
0.0
1.0
2.0
3.0
4.0
5.0
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
Prec
ipita
tion
(inch
es)
Grand Junction Glenwood Spr Vail Pass Loveland Pass Denver Limon
Quiz!What month is the wettest month of the year (on average) for northeastern Colorado AND the driest month of the year for southwestern Colorado?
Photo by Henry Reges
Some climate elements are more consistent than others
Akron 4E Temperature
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100
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2000
2005
Tem
pera
ture
(deg
F)
Summer Average High Temperatures
Summer Average Low Temperatures
Winter Average Low Temperatures
Winter Average High Temperatures
And one more thing to know, the data are good but not great….
MMTSMMTS
Photos by Christopher Davey
This is quickly revealed when we try to explore long-term changes
Dillon Annual (Jan-Dec) Precipitation Totals
0
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Prec
ipita
tion
(inch
es)
So! Based on our available data, can we tell if our climate is changing?
Nolan in funky glasses
Photo by Henry Reges
First, let’s look at temperaturesOf all the state’s long-term weather stations, very few have uninterrupted, consistent data for analyzing climate trends.
Cooperative Weather Stations
in Colorado
Fort Collins Temperatures Fort Collins Average Temperatures from 1889 to 2005
25
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1880
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1985
1990
1995
2000
2005
2010
YEAR
Tem
pera
ture
(deg
F)
Average High Temperature
Mean Temperature
Average Low Temperature
Fort Collins TemperaturesFort Collins Average Temperatures from 1889 to 2005
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1975
1980
1985
1990
1995
2000
2005
2010
YEAR
Tem
pera
ture
(deg
F)
Average High Temperature
Mean Temperature
Average Low Temperature
Akron TemperaturesAkron Average Temperatures (from 1918-2005)
25
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40
45
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55
60
65
70
1880
1885
1890
1895
1900
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1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Tem
pera
ture
(deg
F)
Average High Temperature
Mean Temperature
Average Low Temperature
Akron TemperaturesAkron Average Temperatures (from 1918-2005)
25
30
35
40
45
50
55
60
65
70
1880
1885
1890
1895
1900
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1970
1975
1980
1985
1990
1995
2000
2005
2010
Tem
pera
ture
(deg
F)
Average High Temperature
Mean Temperature
Average Low Temperature
Del Norte TemperaturesDel Norte Monthy Average Temperatures (1920-2005)
20
25
30
35
40
45
50
55
60
65
1880
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Tem
pera
ture
(deg
F)
Average Low Temperature
Mean Temperature
Average High Temperature
Del Norte TemperaturesDel Norte Monthy Average Temperatures (1920-2005)
20
25
30
35
40
45
50
55
60
65
1880
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Tem
pera
ture
(deg
F)
Average Low Temperature
Mean Temperature
Average High Temperature
Montrose TemperaturesMontrose 2 Average Monthly Temperatures (1911-2005)
25
30
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40
45
50
55
60
65
70
1880
1885
1890
1895
1900
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1935
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1945
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1955
1960
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1970
1975
1980
1985
1990
1995
2000
2005
2010
Tem
pera
ture
(deg
F)
Average Low Temperature
Mean Temperature
Average High Temperature
Montrose TemperaturesMontrose 2 Average Monthly Temperatures (1911-2005)
25
30
35
40
45
50
55
60
65
70
1880
1885
1890
1895
1900
1905
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1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Tem
pera
ture
(deg
F)
Average Low Temperature
Mean Temperature
Average High Temperature
What about Denver?!?
Denver (combined)Denver (all 3 stations)
Monthly Average Maximum and Minimum Temperatures
30
35
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50
55
60
65
70
1870
1875
1880
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1900
1905
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1990
1995
2000
2005
2010
Tem
pera
ture
(deg
F)
Denver City Denver WSFO Denver Intl AP
Frost Free Days (Growing Season)
Cheyenne WellsFrost Free Days
Cheyenne Wells, CO Length of Frost Free Period Based on 32 F Threshold
0
25
50
75
100
125
150
175
200
225
1880
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Year
Num
ber o
f Fro
st F
ree
Day
s
Rocky FordFrost Free Days
Rocky Ford 2SE Length of Frost Free Period Based on 32 F Threshold
0
25
50
75
100
125
150
175
200
225
1880
1885
1890
1895
1900
1905
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1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Year
Num
ber o
f Fro
st F
ree
Day
s
AkronFrost Free Days
Akron 4E Length of Frost Free Period Based on 32 F Threshold
0
25
50
75
100
125
150
175
200
225
1880
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Year
Num
ber o
f Fro
st F
ree
Day
s
Fort CollinsFrost Free Days
Fort Collins, CO Length of Frost Free Period Based on 32 F Threshold
0
25
50
75
100
125
150
175
200
225
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1885
1890
1895
1900
1905
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1920
1925
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1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Year
Num
ber o
f Fro
st F
ree
Day
s
Del NorteFrost Free Days
Del Norte Length of Frost Free Period Based on 32 F Threshold
0
25
50
75
100
125
150
175
200
225
1880
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Year
Num
ber o
f Fro
st F
ree
Day
s
Cochetopa CreekFrost Free Days
Cochetopa Creek, CO Length of Frost Free Period Based on 32 F Threshold
0
25
50
75
100
125
150
175
200
225
1880
1885
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1895
1900
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1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
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1975
1980
1985
1990
1995
2000
2005
2010
Year
Num
ber o
f Fro
st F
ree
Day
s
MontroseFrost Free Days
Montrose #2 Length of Frost Free Period Based on 32 F Threshold
0
25
50
75
100
125
150
175
200
225
1880
1885
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1920
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2010
Year
Num
ber o
f Fro
st F
ree
Day
s
Grand Junction 6ESEFrost Free Days
Grand Junction 6ESE Length of Frost Free Period Based on 32 F Threshold
0
25
50
75
100
125
150
175
200
225
1880
1885
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1900
1905
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1975
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2000
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2010
Year
Num
ber o
f Fro
st F
ree
Day
s
DillonFrost Free Days
Dillon 1E Length of Frost Free Period Based on 32 F Threshold
0
25
50
75
100
125
150
175
200
225
1880
1884
1888
1892
1896
1900
1904
1908
1912
1916
1920
1924
1928
1932
1936
1940
1944
1948
1952
1956
1960
1964
1968
1972
1976
1980
1984
1988
1992
1996
2000
2004
2008
Year
Num
ber o
f Fro
st F
ree
Day
s
Evaporation
Bonny Dam Evaporation
Bonny Dam May through Sept Pan Evaporation
0
2
4
6
8
10
12
14
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
Evap
orat
ion
(In)
John Martin Dan EvaporationJohn Martin Dam
May through Sept Pan Evaporation
0
2
4
6
8
10
12
14
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
Evap
orat
ion
(In)
Pueblo Evaporation
Pueblo WSO May through Sept Pan Evaporation
0
2
4
6
8
10
12
14
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
*
2000
2005
Evap
orat
ion
(In)
Grand JunctionGrand Junction
May through Sept Pan Evaporation
0
2
4
6
8
10
12
14
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
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2000
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Evap
orat
ion
(In)
PrecipitationPhoto by Wendy Ryan
Akron PrecipitationAkron 4E Annual (Jan-Dec) Precipitation
0
5
10
15
20
25
30
35
1880
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Prec
ipita
tion
(inch
es)
Cheyenne Wells Precipitation Cheyenne Wells Annual Precip
0
5
10
15
20
25
30
35
1880
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Prec
ipita
tion
(inch
es)
Rocky Ford Precipitation Rocky Ford Annual Precipitation
0
5
10
15
20
25
30
35
1880
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Prec
ipita
tion
(inch
es)
Fort Collins PrecipitationFort Collins Annual Precipitation
0
5
10
15
20
25
30
35
1880
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Prec
ipita
tion
(inch
es)
Durango PrecipitationDurango Annual Precipitation
0
5
10
15
20
25
30
35
1880
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Prec
ipita
tion
(inch
es)
Montrose PrecipitationMontrose Annual Precipitation
0
5
10
15
20
25
30
35
1880
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Prec
ipita
tion
(inch
es)
Grand Lake 1N Precipitation Grand Lake 1N Annual Precipitation
0
5
10
15
20
25
30
35
1880
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Prec
ipita
tion
(inch
es)
Mesa Verde PrecipitationMesa Verde Annual Precipitation
0
5
10
15
20
25
30
35
1880
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
Prec
ipita
tion
(inch
es)
Standardized Precipitation Index 3 MonthFraction of Colorado in Drought
Based on 3 month SPI(1890 - February 2006)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1890
1892
1895
1897
1900
1902
1905
1907
1910
1912
1915
1917
1920
1922
1925
1927
1930
1932
1935
1937
1940
1942
1945
1947
1950
1952
1955
1957
1960
1962
1965
1967
1970
1972
1975
1977
1980
1982
1985
1987
1990
1992
1995
1997
2000
2002
2005
Year
Frac
tion
(in p
erce
nt)
Standardized Precipitation Index 48 monthFraction of Colorado in Drought
Based on 48 month SPI(1890 - February 2006)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1890
1892
1895
1897
1900
1902
1905
1907
1910
1912
1915
1917
1920
1922
1925
1927
1930
1932
1935
1937
1940
1942
1945
1947
1950
1952
1955
1957
1960
1962
1965
1967
1970
1972
1975
1977
1980
1982
1985
1987
1990
1992
1995
1997
2000
2002
2005
Year
Frac
tion
(in p
erce
nt)
Fort Collins Seasonal Patterns of PrecipitationFort Collins Comparison of Monthly Averages
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Prec
ipita
tion
(inch
es)
1890-1929 1930-1969 1970-2005
1890-1929 = 15.23 inches1930-1969 = 14.421970-2005 = 15.69
Akron Seasonal Patterns of Precipitation
Akron 4E Monthly Precipitation Averages
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Prec
ipita
tion
(inch
es)
1890-1929 1930-1969 1970-2005
1905-1929 = 17.58 inches1930-1969 = 16.161970-2005 = 16.06
Rocky Ford Seasonal Patterns of Precipitation
Rocky Ford Seasonal Precipitation Patterns
0.0
0.5
1.0
1.5
2.0
2.5
3.0
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Prec
ipita
tion
(inch
es)
1890-1929 1930-1969 1970-2005
1890-1929 = 12.43 inches1930-1969 = 11.941970-2005 = 11.58
Montrose Seasonal Patterns of Precipitation
Montrose Monthly Precipitation Patterns
0.0
0.5
1.0
1.5
2.0
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Prec
ipita
tion
(inch
es)
1890-1929 1930-1969 1970-2005
1897-1929 = 10.0 inches 1930-1969 = 9.311970-2005 = 9.70
Mountain Snow!
Photo by Wendy Ryan
April 1 Colorado SnowpackAPRIL 1 SNOWPACK
COLORADO STATEWIDE
95
109
119
104
87
109106
130
99
46
126
148146
59
114120
127
10410497
85 87
74
91 93
126
84
105112114
89
65
90 87
52
94
65
107
94
0
20
40
60
80
100
120
140
160
68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 00 02 04 06
Year
Perc
ent o
f Ave
rage
Dry Lake April 1 Snow Course and Snotel
Dry Lake, CO (Elevation 8,400 Ft) April 1 SWE
0
5
10
15
20
25
30
35
1930 1940 1950 1960 1970 1980 1990 2000 2010
SW
E (i
n)
Snow Course April 1 SWE (in)Snotel April 1 SWE (in)
Dry LakeMay 1 – April 1 SWE Difference
Dry Lake, CO (elevation 8,400 feet) Difference in SWE (May 1 - April 1)
-25
-20
-15
-10
-5
0
5
10
15
1930 1940 1950 1960 1970 1980 1990 2000 2010
Diff
eren
ce in
SW
E (i
n)
Snow Course Difference in SWE (in)Snotel Difference in SWE (in)
University CampApril 1 Snow Course and Snotel
Universtiy Camp, CO (Elevation 10,300') April 1 SWE (in)
0
5
10
15
20
25
30
35
40
1930 1940 1950 1960 1970 1980 1990 2000 2010
SW
E (i
n)
Snow Course April 1 SWE (in)Snotel April 1 SWE (in)
University CampMay 1 – April 1 SWE Difference
University Camp, CO (Elevation 10,300') Difference in SWE (May 1- April 1)
-8
-6
-4
-2
0
2
4
6
8
10
12
1930 1940 1950 1960 1970 1980 1990 2000 2010Diff
eren
ce in
SW
E (i
n)
Snow Course Difference in SWE (in)Snotel Difference in SWE (in)
1
Independence PassApril 1 Snow Course and Snotel
Independence Pass, CO (Elevation 10,600') April 1 SWE
0
5
10
15
20
25
30
1930 1940 1950 1960 1970 1980 1990 2000 2010
SW
E (i
n)
Snow Course April 1 SWE (in)
Snotel April 1 SWE (in)
Independence PassMay 1 – April 1 SWE Difference
Independence Pass, CO (Elevation 10,600') Difference in SWE (May 1 - April 1)
-10
-8
-6
-4
-2
0
2
4
6
8
10
1930 1940 1950 1960 1970 1980 1990 2000 2010
Diff
eren
ce in
SW
E (i
n)
Snow Course Difference in SWE (in)Snotel Difference in SWE (in)
Porphyry CreekApril 1 Snow Course and Snotel
Porphyry Creek, CO (Elevation 10,760') April 1 and May 1 SWE (in)
0
5
10
15
20
25
30
1930 1940 1950 1960 1970 1980 1990 2000 2010
SW
E (i
n)
Snow Course April 1 SWE (in)Snotel April 1 SWE (in)
Porphyry CreekMay 1 – April 1 SWE Difference
Porphyry Creek, CO Difference in SWE (May 1 - April 1)
-12
-10
-8
-6
-4
-2
0
2
4
6
8
1930 1940 1950 1960 1970 1980 1990 2000 2010
Diff
eren
ce in
SW
E (i
n)
Snow Course Difference in SWE (in)Snotel Difference in SWE (in)
Mesa LakesApril 1 Snow Course and Snotel
Mesa Lakes, CO (Elevation 10,000') April 1 SWE
0
5
10
15
20
25
30
35
1930 1940 1950 1960 1970 1980 1990 2000 2010
SW
E (i
n)
Snow Course April 1 SWE (in)Snotel April 1 SWE (in)
Mesa LakesMay 1 – April 1 SWE Difference
Mesa Lakes, CO (Elevation 10,000') Difference in SWE (May 1 - April 1)
-15
-10
-5
0
5
10
1930 1940 1950 1960 1970 1980 1990 2000 2010
Diff
eren
ce in
SW
E (i
n)
Snow Course Difference in SWE (in)
Snotel Difference in SWE (in)
Upper San JuanApril 1 Snow Course and Snotel
Upper San Juan, CO (Elevation 10,200') April 1 SWE (in)
0
10
20
30
40
50
60
70
1930 1940 1950 1960 1970 1980 1990 2000 2010
SW
E (i
n)
Snow Course April 1 SWE (in)Snotel April 1 SWE (in)
Upper San JuanMay 1 – April 1 SWE Difference
Upper San Juan, CO (Elevation 10,200') Difference in SWE (May 1 - April 1)
-25
-20
-15
-10
-5
0
5
10
15
1930 1940 1950 1960 1970 1980 1990 2000 2010
Diff
eren
ce in
SW
E (i
n)
Snow Course Difference in SWE (in)Snotel Difference in SWE (in)
Wind!!http://www.state.co.us/oemc/programs/renewable/anemometer.htm
Denver Average Annual Wind SpeedDenver/Stapleton International Airport (DIA as of 1996) Average Annual Wind Speed
0
2
4
6
8
10
12
14
1940 1950 1960 1970 1980 1990 2000 2010
Ave
rage
Ann
ual W
ind
Spe
ed (m
ph)
Colorado Springs Average Annual Wind Speed
Colorado Springs Airport Average Annual Wind Speed (mph)
0
2
4
6
8
10
12
14
1940 1950 1960 1970 1980 1990 2000 2010
Ave
rage
Ann
ual W
ind
Spee
d (m
ph)
Grand Junction Average Annual Wind Speed
Grand Junction Airport Average Annual Wind Speed
0
2
4
6
8
10
12
14
1940 1950 1960 1970 1980 1990 2000 2010
Ave
rage
Ann
ual W
ind
Spe
ed (m
ph
Conclusions!
Installed Pair (14)
Installed Single (61)
Climate Reference Network (CRN)
http://www.ncdc.noaa.gov/oa/climate/uscrn/program.html
Climate Reference Network (CRN)
So, what should I do?Join CoCoRaHS!
Community Collaborative Rain, Hail and Snow Network
For More Information, Visit the CoCoRaHS Web Site
Support for this project provided by Informal Science Education Program,National Science Foundationandmany local charter sponsors.
http://www.cocorahs.org
Colorado Climate CenterData and Power Point Presentations available for downloading
http://ccc.atmos.colostate.educlick on “Drought”then click on “Presentations”