2010: A Year of Extremes?

So far, 2010 has seen record snow depths, record rainfall, a colder than average winter and an unusually warm August throughout the region. Although memory is somewhat subjective, many have had trouble recalling a worse winter, or the last time the area has seen such a long stretch of warm and humid weather in August. In addition, summertime flooding has rivaled and rainfall has exceeded that seen during the infamous summer of 1993.

 

 

 

 

The year began with record snow depths in Sioux City and Mitchell, and temperatures well below average across the region. The table below lists the number of days in January with a temperature below average, the number of days with an average temperature 15 degrees F or more below average, and the maximum snow depth for January. The monthly average temperature for January 2010 is listed in the last column.

 

 

 

Dep. < 0 F

Dep. < 15 F

Snow depth

Avg Temp

Sioux Falls, SD     

17

10

20

10.84 F

Sioux City, IA

18

9

28

13.71 F

Huron, SD

15

9

22

11.58 F

Mitchell, SD

15

8

19

12.94 F

 

 

 

Spring snow melt brought many of the rivers and streams across the area into flood stage, with the James River remaining above flood stage through the present time.

 

 

 

 

 

During the summer, a persistently active weather pattern has resulted in record rainfall throughout much of the Northern Plains. This created a second round of flooding that for many locations was much more significant than that caused by the spring snow melt. The following table lists rainfall from June 1st through present, and is compared to normal and previous record values.

 

 

 

2010  

Normal

Record

Sioux Falls, SD      

20.56"

8.46"

17.08"

Sioux City, IA

17.94"

8.91"

15.48"

Huron, SD

14.32"

7.61"

16.85"

Mitchell, SD

21.50"

7.68"

20.19"

 

 

Excess standing water and southeasterly flow during the month of August has lead to very humid conditions throughout the region, which has generally preventing nighttime lows from dropping to near average values. Although high temperatures have only exceeded 90 degrees a few times and have not reached 100 degrees in southeastern South Dakota, mean temperatures have been above average throughout much of month thus far. This table lists the number of days so far in August (through the 21st) with temperatures above normal, and the number of days with above normal lows.

 

 

 

# of Avg Temp

# of Low Temp

Sioux Falls, SD                                 

15

17

Sioux City, IA

16

18

Huron, SD

15

17

Mitchell, SD

15

16

 

 

 

Such extremes during the period of less than one year beg an explanation. Are these events related to global climate change? It has been suggested that increasing global temperatures will relate to higher extremes in temperature and precipitation (Meehl et al. 2000, Trenberth et al. 2003); however many studies anticipate that wintertime low temperatures will set record warm readings, not record cold. As a means of explanation, it is important to note that “normal isn’t normal;” average temperatures are a compilation of warm and cold periods, and average precipitation is a combination of dry and wet periods. On a larger spatial and temporal scale, 2010 will meld into the long-term gradual trends that make up our earth’s climate.

 

 

 

All images on this website are copyright NWS Sioux Falls, SD unless otherwise noted.

 

 



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