2015 Annual Review

 

The Climate of Alaska for 2015

 

Gerd Wendler, Blake Moore and Kevin Galloway

Alaska Climate Research Center, Geophysical Institute, UAF

 

This review of the climate of Alaska is predominantly based on the 19 first order climatological stations in Alaska, which are operated by NOAA's National Weather Service. Furthermore, the normals used in this analysis are based on the means of the 30-year time period from 1981-2010 and were calculated by NOAA's National Climate Data Center (NCDC). A convenient source for the NCDC normals of all stations for Alaska can be obtained at: http://akclimate.org/Climate/Normals

 

Temperature

 

The mean average annual temperature in 2015 for the first order stations was 35.3°F, a substantial positive departure of 2.7°F from the 30-year normal of 32.6°F. This is a continuation of the warm temperatures from 2014, which had a mean temperature 0.2°F higher than 2015. Deviations of this order are very significant for an area as large as Alaska and a time period as long as a year, as this value surpasses the amount of warming to be expected by climate change over a century.

 

All first order stations had a positive deviation. King Salmon (+4.3°F), McGrath (+3.9°F) and Homer (+3.8°F) showed the highest deviations. The least, but still positive deviations, were found in Talkeetna (+1.8°F), Bettles and Nome (both +1.9°F). In Table 1 the observed mean annual values, the normal and the deviations from the normal are presented.

 

Table 1: Mean temperature for 2015, normal temperature (1981-2010) and deviations from the mean for the 19 first order meteorological stations in Alaska.

 

Station

Temperature

Observed
(°F)

Normal
(°F)

Delta
(°F)

Anchorage

39.7

37.1

2.6

Annette

49.1

46.6

2.5

Barrow

14.1

11.8

2.3

Bethel

34.1

30.7

3.4

Bettles

25.4

23.5

1.9

Cold Bay

40.8

38.8

2.0

Delta Junction

31.5

29.0

2.5

Fairbanks

30.0

27.7

2.3

Gulkana

30.4

28.2

2.2

Homer

42.5

38.7

3.8

Juneau

44.4

42.1

2.3

King Salmon

39.5

35.2

4.3

Kodiak

44.4

40.9

3.5

Kotzebue

26.5

22.9

3.6

McGrath

31.3

27.4

3.9

Nome

29.3

27.4

1.9

St. Paul Island

37.9

35.4

2.5

Talkeetna

37.8

36.0

1.8

Yakutat

42.8

40.3

2.5

Mean

35.3

32.6

2.7

 

 

Furthermore, in Figure 1an isoplete temperature deviation map produced from these values is presented. It can be seen that temperatures in all of Alaska were substantially above normal. The highest deviations were observed in the Southwest, while in the eastern part of Alaska these deviations were more modest. The positive deviations in the Southwest were produced by the strongly positive El Nino, which caused the Pacific surface water temperature to be substantially above normal.

 

 

Figure 1: Isoplete presentation of the temperatures deviations from the normal (1981-2010) for 2015 based on all first order Alaskan meteorological stations.

 

For the 19 first order stations the mean deviation of temperatures by month is presented in Figure 2. September was the only month which was relatively colder than normal by 1.3°F, while August 2015 was very close to normal (+0.1°F). The largest deviations were observed in October 2015 (+5.5°F), February (+5.0°F) and May (+4.9°F).

 

Figure 2: Mean monthly temperature deviation for the 19 first order stations in Alaska by month for 2015.

 

 

Table 2: Mean monthly and annual  temperatures of 2015 for each of the 19 first order meteorological stations in Alaska.

 

Temperature Actuals

Station

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Annual

Anchorage

19.4

24.1

29.7

40.7

49.9

59.5

62.1

58.9

46.4

40.5

23.8

21.5

39.7

Annette

42.1

41.2

43.9

45.2

55.1

58.6

62.0

59.3

53.0

51.3

41.1

35.9

49.1

Barrow

-10.3

-6.6

-11.0

6.7

28.0

40.1

40.5

38.1

31.1

20.6

2.9

-10.6

14.1

Bethel

8.1

17.1

20.5

30.3

46.7

57.1

56.9

52.7

44.0

37.5

24.5

13.8

34.1

Bettles

-12.5

0.1

6.3

27.8

51.6

57.5

60.7

51.1

36.9

25.2

7.4

-7.9

25.4

Cold Bay

31.0

34.5

34.3

34.5

43.6

49.3

51.9

52.5

48.6

42.5

34.7

32.6

40.8

Delta Junction

1.7

7.1

19.5

36.3

55.3

58.2

59.5

52.3

41.3

31.9

11.8

2.9

31.5

Fairbanks

-6.5

1.0

15.5

36.8

55.3

59.8

62.2

54.6

42.4

31.8

9.1

-2.2

30.0

Gulkana

-0.5

5.3

18.5

34.7

51.2

56.8

58.9

52.2

42.6

32.4

13.4

-1.2

30.4

Homer

30.7

32.6

36.7

41.9

49.7

57.8

56.1

55.3

46.2

42.9

32.3

27.9

42.5

Juneau

35.1

31.9

37.1

41.9

54.1

57.0

57.6

56.7

49.2

44.6

36.1

32.0

44.4

King Salmon

21.1

26.8

30.4

36.1

47.9

56.4

57.4

55.3

46.8

42.8

30.3

23.2

39.5

Kodiak

36.3

35.5

36.6

40.0

47.0

54.4

57.4

58.7

50.3

45.5

36.3

34.6

44.4

Kotzebue

3.9

10.2

-2.3

16.4

40.3

51.3

58.7

51.1

40.8

30.5

14.8

1.9

26.5

McGrath

-5.4

8.4

17.6

35.6

52.1

59.3

59.0

54.4

43.6

33.8

16.0

1.1

31.3

Nome

9.2

15.7

6.5

21.5

41.1

47.4

54.9

48.5

40.0

34.3

21.5

11.5

29.3

St. Paul Island

30.1

28.4

26.8

29.6

40.0

44.1

49.3

50.8

47.0

41.6

35.8

31.8

37.9

Talkeetna

16.3

22.9

26.4

38.8

50.9

58.9

59.7

56.2

44.3

39.6

22.7

17.3

37.8

Yakutat

35.3

33.5

35.0

39.0

47.5

53.6

56.0

55.0

47.7

44.0

34.7

31.8

42.8

Statewide

15.0

19.5

22.5

33.4

47.8

54.6

56.9

53.4

44.3

37.5

23.6

15.7

35.3

 

 

 

Table 3: Mean monthly and annual temperature deviations of 2015 for each of the 19 first order meteorological stations in Alaska.

 

Station

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Annual

Anchorage

2.3

3.9

3.1

3.9

2.1

4.3

3.3

2.2

-2.2

5.7

1.6

2.5

2.6

Annette

5.1

3.5

4.2

1.0

4.9

3.5

3.4

0.4

-0.8

4.6

1.1

-1.2

2.5

Barrow

3.1

7.6

1.7

4.9

6.9

4.5

-0.4

-0.9

-1.0

3.4

2.2

-2.8

2.3

Bethel

1.5

6.0

5.3

3.4

4.8

4.6

0.8

-0.8

-1.6

7.2

7.1

3.4

3.4

Bettles

-2.5

5.1

1.9

4.5

7.2

-1.0

1.0

-1.4

-3.7

6.3

8.4

-2.2

1.9

Cold Bay

2.8

5.5

4.2

0.5

3.3

3.0

1.0

0.4

0.5

2.1

0.2

1.5

2.0

Delta Junction

2.7

2.2

5.4

4.1

7.7

0.6

-0.7

-2.5

-2.6

7.8

5.6

0.8

2.5

Fairbanks

1.4

2.3

4.1

4.3

5.9

-0.6

-0.3

-1.5

-2.5

7.6

6.5

1.9

2.3

Gulkana

2.4

-0.2

2.9

2.9

6.0

2.4

1.3

-1.3

-0.7

5.8

7.6

-1.6

2.2

Homer

5.9

6.4

6.8

4.9

5.2

7.2

1.5

1.4

-1.9

4.8

2.8

0.8

3.8

Juneau

6.8

1.8

3.3

1.1

5.5

2.4

0.7

0.8

-0.8

2.2

2.7

2.1

2.3

King Salmon

4.9

8.0

6.3

2.4

3.7

4.9

1.9

0.7

-0.8

9.3

7.4

4.6

4.3

Kodiak

5.8

4.7

3.8

2.4

2.7

4.7

2.9

3.5

0.9

5.0

2.4

3.4

3.5

Kotzebue

6.7

11.0

-3.4

3.1

8.4

5.6

4.1

-0.6

-1.5

6.2

5.7

-0.4

3.6

McGrath

1.1

7.0

6.0

5.9

5.4

1.9

-1.0

-0.2

-1.0

8.7

10.5

4.3

3.9

Nome

4.0

8.3

-3.8

1.0

4.3

-0.4

2.7

-1.6

-2.8

5.6

4.6

2.0

1.9

St. Paul Island

5.0

4.0

2.0

0.4

3.8

1.7

2.1

2.0

1.7

3.0

2.8

2.9

2.5

Talkeetna

2.1

4.8

1.5

2.9

3.1

1.9

-0.4

-0.5

-3.2

6.4

3.2

1.3

1.8

Yakutat

7.2

3.8

3.0

1.2

2.8

2.8

1.7

1.2

-0.7

3.0

2.4

2.2

2.5

Statewide

3.6

5.0

3.1

2.9

4.9

2.8

1.3

0.1

-1.3

5.5

4.5

1.3

2.7

 

 

It was the warmest year for Juneau and Annette, and the second warmest for Ketchikan and Haines, all located in southeastern Alaska. Here, the temperature variations from year to year are normally smaller due to the maritime influence when compared to the Interior (a continental climate), where the moderating influences of the ocean are less pronounced. Outside of the Southeast, Anchorage, Homer and Kotzebue each had the second warmest years on record.

 

The highest temperatures of all stations for the year were 89°F observed in Talkeetna on the 15th of June and in Fairbanks on the 6th of July 2015. Annette was the station with the highest mean annual temperature at 49.1°F. The highest mean monthly temperature was observed in July in Fairbanks at 62.2°F, followed very closely by Anchorage at 62.1°F and Annette at 62.0°F. Fairbanks observed 11 days at which the maximum temperature was equal to or surpassed 80°F; the long term mean is 12 days.

 

On the other side of the coin, Barrow, at 14.1°F, observed the lowest mean annual temperature, while Bettles, situated in the northern Interior, observed the lowest absolute temperature of all stations at -56°F on the 26th and 27th of January. Bettles also observed the lowest mean monthly temperature at -12.5°F in January 2015.

 

In Table 4 new monthly temperature records are presented. These records were mostly observed in May, which had been very warm and in June. For all other months no new monthly temperature records were observed.

 

 

Table 4: Monthly mean temperature record for select stations in Alaska.

 

 

Temperature Records

Month

Station

New
Record

Old
Record

Year of
old Record

May

Bettles

51.6

51.0

1990

May

Kotzebue

40.3

39.4

2004

May

Barrow

28.0

28.0

1991

May

Delta Junction

55.3

54.2

1981

May

Fairbanks

69.2

67.6

1995

May

Gulkana

51.2

50.5

2004

May

Haines Airport

55.0

55.0

1915

May

Juneau

54.1

52.7

2005

May

King Salmon

39.7

38.8

1990

May

Ketchikan

55.0

53.5

1993

May

Kotzebue

40.3

39.4

2004

May

Skagway Airport

55.1

52.9

2014

Jun

Anchorage

59.5

59.4

2013

Jun

Barrow

40.1

39.0

2013

Jun

Homer

57.8

56.1

1936

Jun

King Salmon

56.4

55.3

2013

 

 

 

Precipitation

 

The mean annual precipitation of the 19 stations was 37.28", which is 9% above the long-term mean. As reported previously (Shulski and Wendler 2007), there is a very large variation in the precipitation totals, when traversing from the Southeast to Arctic Alaska. For example, Yakutat reported for 2015 a total of 148.14", while Barrow in Northern Alaska, recorded a value of just 5.73" for the same time period. It is even more remarkable that Barrow for 2015 reported above normal precipitation at 26%. This large gradient in precipitation explains the fact that the most glaciers are found in Southern Alaska, with many calving in the ocean, while in the Brooks Range, in Northern Alaska, with much colder temperatures, glaciers are less common and smaller in size. In Figure 3 the precipitation values are presented across Alaska, however, isolines are not provided, as large variations can occur over short distances especially in mountainous terrain and in the summer due to localized shower activities. The figure shows that most of Alaska is close to normal in precipitation. Juneau (136%), Fairbanks (133%) and Barrow (126%) recorded relatively the highest amount of precipitation. There was only one station measuring a deficit of precipitation in excess of 10%: Delta Junction at 79%. More details can be seen in Table 5, in which the actual deviation values by station are presented.

 

Figure 3: Precipitation deviations (%) from the normal (1981-2010) for 2015 based on all 19 first order stations in Alaska.

 

 

 

Table 5: Observed precipitation for 2015, normal precipitation (1981-2010) and deviations from the mean for the 19 first order stations in Alaska.

 

 

Station

Precipitation

Observed
(in)

Normal
(in)

Delta
(in)

Delta
(%)

(%)

Anchorage

18.81

16.58

2.23

13%

113%

Annette

108.75

101.63

7.12

7%

107%

Barrow

5.73

4.53

1.20

26%

126%

Bethel

19.30

18.54

0.76

4%

104%

Bettles

16.42

14.90

1.52

10%

110%

Cold Bay

38.86

41.67

-2.81

-7%

93%

Delta Junction

9.19

11.62

-2.43

-21%

79%

Fairbanks

14.38

10.81

3.57

33%

133%

Gulkana

12.63

11.26

1.37

12%

112%

Homer

26.92

24.34

2.58

11%

111%

Juneau

84.96

62.27

22.69

36%

136%

King Salmon

24.96

19.49

5.47

28%

128%

Kodiak

76.75

78.00

-1.25

-2%

98%

Kotzebue

10.47

11.00

-0.53

-5%

95%

McGrath

18.39

18.00

0.39

2%

102%

Nome

16.92

16.81

0.11

1%

101%

St. Paul Island

27.83

23.67

4.16

18%

118%

Talkeetna

29.00

27.97

1.03

4%

104%

Yakutat

148.14

155.12

-6.98

-4%

96%

Mean

37.28

35.17

2.12

9%

109%

 

 

Table 5 clearly shows that most observations are relatively close to the expected values. The mean of the 19 stations is 109%, or 9% above the long-term mean. The fact that the relatively largest positive deviation is found at Barrow is not surprising as the temperatures of the North Slope have increased more than any other area in Alaska, and more open water is observed for the Beaufort and Chukchi Seas, supplying a ready source of water vapor (Wendler et al. 2014).

 

In Figure 4 the annual precipitation values from normal are presented for the 19 stations and it shows that the deviations from normal are fairly limited.  Precipitation can vary substantially from year to year, especially in relative dry areas of Northern Alaska, where one major storm can make a noticeable contribution to the annual value.

 

 

Figure 4: Annual precipitation deviation from the normal for the 19 first order stations in Alaska for 2015.

 

Figure 5: Precipitation deviation for the mean of the 19 first order stations in Alaska by month for 2015.

 

Looking at the monthly precipitation deviations from normal for 2015 (Figure 5), it can be seen that that the year started off dryer than normal, then was wetter than expected from March to May. June was the driest month compared to normal for the year, and this helped ignite the wildfire season. June was followed by three wetter than normal months. October was near normal. November was the wettest month compared to normal. December ended the year dryer than normal.

 

Looking at the actual annual values, the highest precipitation total for the year was observed in Yakutat at 148.14" followed by Annette (108.75"). Both are located in Southeast Alaska, well known for its heavy rains. Yakutat held also the greatest monthly total at 21.46", observed in September 2015. No totally dry month was observed, but the lowest monthly value was observed in Barrow at 0.04" in December 2015. Looking at daily values, the highest was again found at Yakutat with 4.39". Juneau's annual precipitation total of 84.56" was only 0.19" short of the record set in 1991. May was very dry in the Southeast, and a number of new record low monthly precipitation totals were set. See Table 6.

 

 

Table 6: Monthly precipitation records for select stations in Alaska. Records with * represent new record low monthly precipitation totals.

 

 

Precipitation Records

Month

Station

New
Record

Old
Record

Year of
old Record

Jan

Craig

11.64

11.05

2009

Jan

Haines Airport

11.71

10.87

1983

Jan

Juneau

11.98

10.17

1939

Apr

Petersburg

12.11

11.10

1952

May

Barrow

0.34

0.30

2014

May

Annette *

0.50

1.34

1946

May

Juneau *

0.52

0.84

2004

May

Ketchikan *

0.68

2.12

2010

May

King Salmon

3.32

3.20

1941

May

Sitka *

0.34

0.72

2014

May

Yakutat *

1.62

2.58

2009

Jul

Juneau

10.40

10.36

1997

Sep

Anchorage

1.56

1.41

2012

Sep

Anchorage

7.71

7.61

2004

Sep

Fairbanks

3.74

3.05

1960

Nov

King Salmon

4.84

3.89

2003

 

Snowfall

 

Precipitation falls in summer as rain, but in winter as snow. "Winter" is, of course, much longer in Northern Alaska, e.g. Barrow, then in the Southeast, e.g. Annette. In Table 7 the annual snowfall for the stations is presented. It should be pointed out that four stations, namely Delta Junction, Gulkana, Homer and Talkeetna, do not report snowfall amounts.

 

Table 7: Observed snowfall for 2015, normal snowfall (1981-2010) and deviations from the mean for the 15 first order stations in Alaska which report snowfall.

 

Station

Snowfall

Observed
(in)

Normal
(in)

Delta
(in)

Delta
(%)

(%)

Anchorage

33.9

74.5

-40.6

-54%

46%

Annette

10.6

34.9

-24.3

-70%

30%

Barrow

38.2

37.7

0.5

1%

101%

Bethel

46.3

61.8

-15.5

-25%

75%

Bettles

113.9

91.4

22.5

25%

125%

Cold Bay

45.8

73.1

-27.3

-37%

63%

Fairbanks

70.0

65.0

5.0

8%

108%

Juneau

68.2

86.7

-18.5

-21%

79%

King Salmon

44.4

46.6

-2.2

-5%

95%

Kodiak

36.8

68.9

-32.1

-47%

53%

Kotzebue

48.1

59.8

-11.7

-20%

80%

McGrath

75.9

97.3

-21.4

-22%

78%

Nome

63.5

75.7

-12.2

-16%

84%

St. Paul Island

67.1

59.8

7.3

12%

112%

Yakutat

87.0

143.4

-56.4

-39%

61%

Mean

56.6

71.8

-15.1

-21%

79%

 

The table shows that on average for the 15 stations a deficiency of 21% in snowfall is being observed. This result looks astounding at first, as the total precipitation of all stations was 9% above normal. However, considering the substantially above normal temperatures, a greater percentage of the precipitation has fallen as rain instead of snow and the observed values do make sense. The annual snowfall deviation for each station is presented in Figure 5.

 

Figure 6: Mean annual snowfall deviations for fifteen of the first order stations in Alaska for 2015.

 

 

Positive deviations were found for St. Paul Island (12%), St., Fairbanks (8%) and Barrow (1%). The highest negative deviation was found at Annette (-70%). Here the mean annual temperature is close to the freezing point, and the positive temperature deviation observed in 2015 resulted in a higher percentage of rain.

 

Fairbanks set a new monthly snowfall record in September with 13.5", topping the 12.9" record from 1992. The one-day snowfall of 11.2" in Fairbanks on the 29th set a new daily record for any September day, breaking the 1992 record of 7.8" that fell in the 13th. For November, Bettles received 50.6" of snow, a new November record, breaking the 41.6" record set in 1967. Bettles also record a total of 71.8" of snow from September 1st to November 30th, a new record for this time span, shattering the 59.3" from 1979.

 

 

Forest Fires

 

Here we will discuss one major climate related event, the forest fire statistics of last summer, as these were remarkable. A total of 5.14 millions acres were burnt during the summer of 2015, the 2nd highest amount in more than 60 years, the time span for which we have good records. It is also six times the burnt area burnt in California during this last summer, as well as more than 15 times the acreage burnt in all of Alaska in 2014. In Figure 7 the areas that were burned in 2014 and 2015 are shown.

 

 

Figure 7: Area burned by wildfires in Alaska for 2015 (red) and 2014 (green). Note that most of the area burned occurred in the interior, specifically in then middle Yukon Flats, and comprising mostly of boreal forest. Data courtesy of the Alaska Interagency Coordination Center.

 

The climatological conditions were very different between the two extreme wildfire years of 2004 and 2015. Summer 2015 had a very warm and dry spring, which dried out the surface, and the fires, which started in May, spread. From the middle of June until the middle of July more than 80% of the annual value were consumed by fires. The decrease in the burning rate in late July and August is due to above normal precipitation. In contrasts to this, the severe fire season of 2004 started later in summer, however, lasted longer, which can be clearly shown in Figure 8.

 

Figure 8: Cumulative percent area burned by day for wildfires in Alaska for 2004 (blue) and 2015 (orange). Data courtesy of the Alaska Interagency Coordination Center.

 

This is a fairly brief annual review, for more exhaustive monthly statewide summaries as well as some select station summaries, including more detail on record events, please visit the ACRC website at: http://akclimate.org. For seasonal values visit ACCAP's website for the Alaska's Climate Dispatch at: http://ine.uaf.edu/accap/. In addition, the papers referenced below can be accessed from the ACRC's website at: http://akclimate.org.

 

 

References

Shulski, M., and Wendler, G. 2007. The Climate of Alaska. University of Alaska Press, 216 pp

 

Wendler, G., M. Shulski and B. Moore 2010: Changes in the Climate of the Alaskan North Slope and the ice concentration of the adjacent Beaufort Sea. Theoretical and Applied Climatology. 99, 67-74

 

Wendler, G. and M. Shulski 2010. A Century of Climate Change for Fairbanks, Alaska. Arctic 62(3): 295-300

 

Wendler, G. L. Chen and B. Moore 2012. The first Decade of the New Century: A cooling trend for most of Alaska. The Open Atmospheric Science Journal 6, 111-116

 

G. Wendler & L. Chen & B. Moore, 2013, Recent Sea Ice Increase and Temperature Decrease in the Bering Sea area, Alaska , Theoretical and Applied Climatology, 114, No.1-2

 

G. Wendler, B. Moore, K. Galloway, 2015, Strong Temperature Increase and Shrinking Sea Ice in Arctic Alaska , The Open Atmospheric Science Journal , 8, 7-15

 

This information consists of preliminary climatological data compiled by the Alaska Climate Research Center, Geophysical Institute, University of Alaska Fairbanks. For more information on weather and climatology, contact the center at 474-7885 or visit the center web site at http://akclimate.org. Please report any errors to webmaster@akclimate.org.