2010 Annual Climatic and Hydrologic Summary for 
Western South Dakota and Northeastern Wyoming

Temperature and Precipitation Summary

Temperatures averaged 0.3 degrees above normal for the region. Gillette 4SE in northeast Wyoming was the warm spot, averaging 2.6 degrees above normal. The cold spots were at Colony in northeast Wyoming and Newell where temperatures averaged 1.9 degrees below normal. Precipitation averaged 115 percent of normal across the region, with record rainfall being reported at Lemmon and Dupree. The average surplus for the year was 2.66 inches. Across western South Dakota the highest precipitation total was at Deadwood 2NE where 34.44 inches of precipitation fell. Oglala 1S was the dry spot with only 14.22 inches. In northeastern Wyoming, Upton 14ENE was the wet spot with 22.92 inches, while Colony was the dry spot with 13.20 inches. 

All-time annual record rainfall was recorded in Lemon and Dupree. Lemmon had 25.56 inches of precipitation which breaks their old record of 24.14 inches set in 1982. Dupree had 26.20 inches which breaks their old record of 25.24 inches in 1982. At Camp Crook, Devils Tower, Faith, Hot Springs, Milesville 5NE and Redig 11NE yearly precipitation was also in the top ten all-time.  (A detailed table on all records set in 2010 can be found below).
 
Click here for 2010 precipitation totals

Significant storms of 2010 

Snowstorms of 2010

The first significant snowfall of 2010 occurred on January 6 when 3 to 5 inches of snow fell on western South Dakota and the Bear Lodge Mountains. Nearly three weeks later on January 24 and 25 a strong upper level storm system brought 8 to 15 inches of upslope snows to the northern Black Hills and Bear Lodge Mountains.
 
An upper level storm system on February 4 brought 3 to 7 inches of snow to the Black Hills, southwestern South Dakota and to the eastern and northern Foothills. A week later on February 13 another upper level disturbance brought 4 to 7 inches of snow to the Bear Lodge Mountains and the northern Black Hills.
 
March was a quiet month with only one significant snowfall. On March 10-11 a strong upper level low pressure system moved through the Central Plains bringing 4 to 8 inches of snow to the Black Hills and far western South Dakota.  

April started out on the white side. On April 1 and 2, a strong upper level storm system brought snow to northeast Wyoming, the Black Hills and northwest South Dakota. Across the northern Black Hills and Bear Lodge Mountains 12 to 18 inches of snow fell, with 6 to 12 inches across the plains of Campbell and Crook counties in northeast Wyoming. The northern and eastern foothills, the central Black Hills and northwest South Dakota saw 4 to 8 inches of snow. Another upper level disturbance brought 3 to 6 inches of snow to Fall River County and western Custer County in southwest South Dakota, and to Weston County in northeast Wyoming on April 6. Two weeks later on April 23 and 24, another strong upper level low pressure system brought 4 to 8 inches of snow to elevations above 6000 feet in the Black Hills and Bear Lodge Mountains.

On May 1 an upper level storm system brought 6 to 12 inches of snow to elevations above 5500 feet in the northern Black Hills and Bear Lodge Mountains. A week later on May 5 and 6, another upper level storm system brought 4 to 8 inches of snow to far northwest South Dakota, the Bear Lodge Mountains and far northern Campbell and Crook counties in northeast Wyoming. A slow moving upper level trough brought heavy snow to the Black Hills and Bear Lodge Mountains on May 10 through 12. During the three days 10 to 18 inches of snow fell above 5500 feet, with 4 to 10 inches falling below 5500 feet. 

On November 9 an upper level disturbance produced a narrow band of heavy snow over central Crook County where 12 to 17 inches fell. Two weeks later another upper level disturbance brought widespread snow to the region on November 22. On the northeast Wyoming plains snowfall averaged 3 to 8 inches, with the South Dakota plains averaging 2 to 6 inches. At the end of November a powerful upper level low pressure system brought heavy upslope snows to the northern Black Hills and Bear Lodge Mountains on November 29. Snowfall of 20 to 30 inches was reported in the northern Black Hills and Bear Lodge Mountains, with 6 to 12 inches of snow falling over the northern foothills.

An upper level disturbance brought 4 to 8 inches of snow to the northern Black Hills and Bear Lodge Mountains on December 10. The last two days of the year saw a strong upper level low pressure system move through the Central Plains bringing widespread snow to the region. The heaviest snows fell in south central South Dakota and the Black Hills where 8 to 12 inches was reported. Elsewhere on the South Dakota plains 4 to 8 inches of snow fell. Across the northeast Wyoming plains 5 to 10 inches of snow fell.

2010 Severe Weather Summary

The 2010 severe weather season was an active one. The National Weather Service in Rapid City issued 311 severe thunderstorm warnings and 22 tornado warnings from April through October. During the severe weather season, 25 tornadoes were reported, with 23 occurring in western South Dakota and two in northeast Wyoming. The largest hail reported was the size of softballs from Angostura Reservoir to Maverick Junction on May 24. The highest measured winds were 87 mph near the Montana state line in northern Campbell County on June 30.    

Windstorms of 2010

A strong pressure gradient developed over western South Dakota on April 9, producing strong northwest winds of 35 to 45 mph with gusts to 60 mph on the plains of western South Dakota, mainly north of I-90. The strongest wind gust reported was 68 mph, 4 miles northwest of Rapid City.  On May 4 a deep low pressure system in North Dakota produced a strong pressure gradient across western South Dakota. Strong northwest winds of 35 to 45 mph with gusts in excess of 60 mph were common. The strongest wind gusts reported were 76 mph at Buffalo.
 
On October 26 and 27 an intense storm system moved across the northern plains bringing strong northwest winds to the region. The storm produced sustained winds of 35 to 45 mph with gusts to 60 mph or more common. The strongest wind gust reported was at Union Center where winds gusted to 70 mph. On November 18 strong downslope winds of 60 to 80 mph were reported in the Spearfish area. The strongest wind gust reported was 80 mph, 5 miles west of Spearfish.  

2010 Flooding Summary

Frozen rivers were common in January, but the river ice began to break up along the Cheyenne, White, and Little White Rivers in southwestern and south central South Dakota in February. However, thick, solid ice cover remained over northwestern South Dakota.
 
In March, ice break-up and several ice jams caused flooding along the White River from south of Interior to the Missouri River from March 4 to 14. Flood waters south of Interior reached the shoulder of Highway 44. Between Murdo and White River along Highway 83, the river was reported to be a half mile wide. South of Reliance along Highway 47, the gage height reached a preliminary stage of 23.4 ft (flood stage is 15 ft) which makes it one of the top five highest crests on record. Also minor flooding due to snow melt was observed along the White River in Shannon County mostly near and along the Nebraska border.
 
Heavy rain on April 23 caused high stream and river levels across western and south central South Dakota. The White River, the Little Missouri River, and several small streams in the Black Hills reported quick rises from the heavy rain. However, only low land flooding along the creeks and streams were observed. 
 
May was a very active month as the heavy rain season began and the snow melted. On May 11, heavy rain fell across northeastern Wyoming with Gillette reporting 1.86 inches and Devil’s Tower reporting 1.20 inches. This heavy rain caused minor flooding along the Belle Fourche River downstream from Keyhole Reservoir and along Beaver Creek north of Alva.
 
On May 18, at least four inches of rain fell in less than three hours causing flash flooding along Oak Creek, Hay Creek and Beaver Creek in northeastern Crook County. Oak Creek Road and Mona Road were severely damaged. At one crossing, during the worst part of the flooding, the water was at least 3 feet above the road and over 30 feet deep. There was a lot of debris and the water cut away at the road base at all the culverts in the area.
 
On May 21, scattered thunderstorms brought heavy rain and some small stream flooding to the Badlands and to the southern portion of the Cheyenne River Reservation.
 
On May 24, a strong low pressure system moved across the area producing tornadoes, large hail, damaging winds, widespread flash flooding, and winter weather. The thunderstorms produced heavy rains that caused flash flooding in Pennington, Meade, Custer, and Fall River counties. Here is a summary of the flooding reports received by the National Weather Service: in Pennington County water was reported over several roads including 156th St, 159th St, 160th St, 161st St, Elk Vale Rd north of the Flying J Truck Stop, Dyess Rd, Seger Ave, Nike Rd and County Rd. In Keystone a few basements flooded. Along Rapid Creek, the water was flowing through the playground at Sioux Park and over the bike path in Founder’s Park as well as areas around the fairgrounds flooded. Rapid Creek came close to flowing over South Valley Dr and Green Valley Dr in Rapid Valley. In Meade County several gravel roads flooded including Husker Place north of Rapid City, Horse Shoe Rd, Elk Creek Rd, Antelope Creek Rd, 220th Ave, Royal Ranch Rd and Justice Rd north of Box Elder. In Custer County several roads were covered with water including Battle Creek Rd, Crooked Canyon Rd and Tiffany Rd. Flooding was reported along Battle Creek, Iron Creek, Grace Coolidge Creek, Grizzly Bear Creek, Beaver Creek and Lame Johnny Creek. In Fall River County water was reported over Beaver Creek Road at Beaver Creek, South Sixth Street and Joplin Ave in Hot Springs. Flooding was also reported along Cascade Creek and in a subdivision northwest of Hot Springs near Cottonwood Dam.
 
On May 29, two to four inches of rain fell over southeastern Tripp County. This heavy rain caused flooding of small creeks, streams, and low lying areas. Water also covered a county road south of Winner.
 
Additional flooding continued in June. On June 1, torrential rain of 1.5 to 2.5 inches fell in less than an hour fell over Todd and Tripp Counties in south central South Dakota. Water was reported over a gravel road south of Winner and the heavy rain ponded in fields and other low lying areas.
 
On the afternoon of June 10, one to two inches of rain fell from east of Custer to Hermosa. Grace Coolidge Creek was reported to be overflowing its banks southwest of Hermosa causing minor flooding.
 
On June 13 and 14 minor flooding was reported over southwestern South Dakota. Strong thunderstorms produced rainfall amounts of two to four inches. Runoff from this rain caused minor flooding over Custer, Fall River and Shannon Counties.
 
During the evening of June 16, four to seven inches of rain fell around the Dupree, SD area. Flash flooding and flooding occurred in Dupree and along Bear Creek, Ash Creek, and the Moreau River. Besides the flooding, 16 tornadoes were reported around the Dupree area; the strongest of which was rated an EF-2 on the Enhanced Fujita damage scale. Several homes flooded from the heavy rain and several sections of Highway 212 were covered with water at least a foot deep.
 
Heavy rain over the southern Black Hills on June 19 and 20 caused flooding in Wind Cave National Park and along Lame Johnny and Beaver Creeks. Water was reported over Custer County 101 between Highway 385 and Highway 79, and over Beaver Creek Road south of Buffalo Gap.
 
On June 22 and 23, brief heavy rain of two to four inches caused minor flooding across several portions of northeastern Wyoming and western South Dakota. In the Belle Fourche River Basin in northeastern Wyoming, the heavy rain caused minor flooding of gravel roads around Rozet and Moorcroft. The Belle Fourche River was reported out of its banks from Hulett to west of Colony. In western South Dakota, minor flooding occurred in the campground around Cold Brook Reservoir, western areas of the Rosebud Reservation, and along the lower portions of Battle Creek and Rapid Creek
 
During the late afternoon and evening of July 10, an upper level wave moved across South Dakota as a surface low pressure system set up over south central South Dakota. As thunderstorms began in the afternoon, two to three inches of rain fell causing minor flooding of small creeks and streams in northern Jackson County and east central Tripp County. No reports of damaged were received due to the minor flooding.
 
Additional storms on July 11 caused low-land flooding and ponding of water over the central Black Hills. Scattered thunderstorms dropped two to three inches of rain from Rochford to Pringle. Small creeks and streams rose quickly from the runoff with minor low-land flooding along Spring Creek near Hill City.
 
Two to four inches of rain overnight on July 18-19 caused flooding of low lying areas in eastern Pennington, southeastern Meade and southern Haakon counties. Minor flooding in Rapid City occurred as heavy rain and hail overwhelmed storm drains leading to ponding of water on several city streets. Rapid Creek rose one to three feet from Rapid City to Farmingdale due to runoff from the heavy rain.
 
During the morning of July 21, three to five inches of rain fell over northwestern South Dakota. The heavy rain covered most of Harding and Perkins Counties. Minor flooding of small creeks and streams were reported and water ran over a few rural roads when water was unable to quickly pass through small culverts already flowing at maximum capacity. The excess water also was responsible for raising the elevation at Shadehill Reservoir back into the flood pool.
 
During the afternoon of July 21, minor flooding occurred in Moorcroft and Upton due to heavy rain from strong thunderstorms. Over two inches of rain was reported in an hour in Moorcroft.
 
On July 23, heavy rain caused flooding from White Butte to Lemmon along Highway 12 in northeastern Perkins County. In Lemmon, several streets were flooded when one to two inches of rain fell in less than an hour.
 
On July 29, brief heavy rain caused minor flooding on the Cheyenne River Reservation in southern Ziebach County. Rainfall amounts of two to three inches in three hours caused minor flooding along Cherry Creek, Red Scaffold Creek and Rattlesnake Creek. Later in the day, minor flooding occurred along Spring Creek from Highway 16 downstream to south of Folsom. Also in Hot Springs water briefly covered the low water crossings in town.
 
The active weather pattern continued into early August as flooding was observed the first three days of the month. On August 1 and 2, heavy rain of one to three inches fell over Crook County, Wyoming causing small stream flooding. On August 3, a strong upper level disturbance combined with excessive moisture caused flash flooding over the northern Black Hills and foothills with widespread minor street flooding and small stream flooding across western South Dakota. Four inches of rain in two hours caused widespread street flooding in Lead and Deadwood. Water was swiftly flowing down Main Street and Sherman Street in Deadwood at a depth of 6 to 12 inches. In Deadwood, a parking garage was flooded as well as several cars, basements, and businesses. Minor street flooding was also reported in Rapid City, Belle Fourche, Sturgis, Hot Springs, and Custer due to heavy rain overwhelming storm drains. Small stream flooding and ponding of water in low lying areas was common throughout western South Dakota from the heavy rain.
 
On August 9 and 16, excessive rainfall of two to three inches caused minor flooding of small streams and low lying areas of Fall River, Custer, and Shannon Counties. The low water crossings in Hot Springs flooded and low lying areas in the Minnekahta Valley flooded.
 
No flooding occurred during September.  

Heavy rain across the northern Black Hills on October 9-10 contributed to a retaining wall collapsing in Lead, minor mud slides and flooded basements. Twenty-four hour rainfall reports of 4.64 inches were reported in Lead with 4.12 inches in Deadwood. Automated stream gaging stations only showed minor rises with the heavy rain, but water was reported flowing in Bear Butte Creek through Boulder Canyon into Sturgis. 

River ice began to develop in November, with several creeks and streams completely ice covered by December ending the flooding threat for the year.

Temperature Extremes

Station

            High

Date(s)

            Low

Date

Buffalo *

98

August 10

-19

January 8

Cottonwood

108

August 10

-28

January 8

Deadwood 2NE

97

August 10

-13

January 7, 8

Faith

104

August 10

-18

January 8

Gillette

100

July 31, August 22

-15

November 23

Interior

107

August 10

-22

January 8

Pine Ridge *

104

August 10

-32

January 8

Phillip *

110

August 10

-23

January 8

Rapid City Airport*

102

August 27

-18

January 8

Winner

102

August 10

-20

January 9, 10

 Precipitation Extremes

Station

Rainfall

Date

Snowfall

Date

Buffalo *

1.57

July 21

Not available

Cottonwood

1.65

July 22

7.8

November 22

Deadwood 2NE

3.43

October 9

16.1

April 2

Faith

2.41

June 23

6

April 2, Nov. 22

Gillette

1.38

June 23

6

April 2, Nov. 22

Interior

1.25

October 9

5.5

22-Nov

Pine Ridge *

1.5

June 13

Not available

Phillip *

1.04

April 23

Not available

Rapid City

1.81

May 10

5.8

November 22

Winner

2.15

June 11

12.0

December 31

 * Data is from the automated weather station

RECORDS SET IN 2010

ALL TIME DAILY/MONTHLY RECORDS SET IN 2010
LOCATION
DATE
NEW RECORD
OLD RECORD
DATE
Dupree
06/17/2010
4.86 inches precipitation
4.27 inches precipitation
08/21/1933
ANNUAL PRECIPTATION RECORDS SET IN 2010
LOCATION
YEAR
NEW RECORD
OLD RECORD
YEAR
Dupree
2010
25.30 inches precipitation
25.24 inches precipitation
1982
Lemmon
2010
24.88 inches precipitation
24.14 inches precipitation
1982
MONTHLY RECORDS SET IN 2010
LOCATION
DATE
NEW RECORD
OLD RECORD
DATE
Devils Tower
May
48.5 degree avg. temperature
48.6 degree avg. temperature
1995
Maurine 12SW
October
50.9 degree avg. temperature
49.4 degree avg. temperature
1980
Cottonwood 2E
November
-23 degree temperature
-22 degree temperature
1940
Spearfish
November
79 degree temperature
78 degree temperature
1999, 2005, 2010
SINGLE DAY RECORDS FOR MONTH SET IN 2010
LOCATION
DATE
NEW RECORD
OLD RECORD
DATE
Devils Tower
01/25/2010
1.00 inches of precipitation
0.54 inches of precipitation
01/21/1986
Devils Tower
01/25/2010
9.0 inches of snowfall
6.3 inches of snowfall
01/21/1986
Dupree
06/17/2010
4.86 inches of precipitation
3.38 inches of precipitation
06/05/2008
Devils Tower
11/10/2010
10.0 inches of snowfall
7.0 inches of snowfall
11/10/1978
Winner
12/31/2010
12.0 inches of snowfall
11.0 inches of snowfall
12/10/1989
Winner
12/31/2010
1.10 inches of precipitation
0.85 inches of precipitation
12/25/1964

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