NWS La Crosse Top 10 Weather Events

Top 10 Weather/Climate
Events in 2010

Here is a listing of the Top 10 Weather Events for 2010 in the NWS La Crosse Warning and Forecast Area. This includes areas of southeast Minnesota, northeast Iowa, and southwest/central Wisconsin.

This listing is the result of voting among NWS La Crosse staff members (12), Emergency Management Directors (7), and members of the media (10).

Climate related data and numerous images courtesy of the Midwestern Regional Climate Center (http://mcc.sws.uiuc.edu/).

Updated: 1/3/11 - tjs

For additional information, contact:

Todd Shea, Warning Coordination Meteorologist, or
Jeff Boyne, Climate Services Focal Point

Honorable Mention: June 26-27 Severe Weather

A cluster of thunderstorms developed into a squall line and bowed through southern Minnesota producing damaging wind gusts during the late evening hours of June 26th. A hurricane force gust of 74 mph was recorded at Dodge Center, MN (Dodge County) with other wind damage across neighboring Mower County, MN from straight-line winds estimated from 70 to 85 mph.

For a more detailed summary of this event, click here: http://www.crh.noaa.gov/arx/?n=jun2710

Honorable Mention: December Snowfall

A very active weather pattern led to at least 4 winter storms with high snowfall across much of the region during December 2010. The first two weekends saw heavy snow followed by two storms during the week leading up to Christmas. The snow was heaviest across southeast Minnesota where 35 to 41 inches of snow fell. The following locations had their snowiest December:

Location	December 2010 Snowfall	Previous Record December Snowfall (Year)
Rochester, MN	41.3"	35.3" (2000)
Grand Meadow, MN	40.6"	34.6" (2008)
Winona Dam 5A	39.0"	30.0" (1968)
La Crescent Dam 7	37.8"	30.0" (2008)
Preston, MN	37.7"	33.8" (2008)
Caledonia, MN	36.1"	28.1" (2008)
Waukon, IA	36.0"	35.5" (2008)
Elkader, IA	31.1"	25.3" (2009)
Minnesota City Dam 5	29.2"	27.4" (2008)
Osage, IA	28.7"	27.6" (2008)
Alma Dam 4	27.0"	25.5" (1969)

There were even a few locations that had their snowiest month ever.

Location	December 2010 Snowfall	Previous Record for Snowiest Month (Month & Year)
Rochester, MN	41.3"	35.3" (Dec 2000)
La Crescent Dam 7	37.8"	34.8" (Mar 1959)
Preston, MN	37.7"	33.8" (Dec 2008)
Waukon, IA	36.0"	35.5" (Dec 2008)

10. Warm Spring

The lingering effects of a strong El Nino helped produce the second warmest spring on record for most of the region. Typically El Ninos prevent arctic intrusions during the early and mid spring, and this one was no different. Many areas had an exceptionally warm March (7th warmest at both La Crosse, WI and Rochester, MN) and April (2nd warmest at Rochester, MN and 3rd warmest at La Crosse, WI).

As a state, Wisconsin finished with the 2nd warmest April on record. Minnesota had the 3rd warmest April ever and Iowa had their 5th warmest.

The following table shows data for meteorological spring (March 1st through May 31st):

Location	Average Temperature	Normal Temperature	Difference from normal	Record (Year)
La Crosse, WI	52.0	47.8	+4.2	53.9 (1977)
Rochester, MN	50.2	44.1	+6.1	52.1 (1977)


April 2010 temperature departure from normal. (Click on image to enlarge)	Meteorological spring temperature departure from normal (March 1 - May 31st). (Click on image to enlarge)

9. Early End to 2009-2010 Snow Season

In conjunction with the abnormally warm spring, the end of the snowfall season was also abnormally early. The last measurable snowfall occurred in late February 2010 (Feb.20th in La Crosse, WI and Feb.23rd in Rochester, MN) setting records for the earliest final snowfall of the season. Normally, the last measurable snow occurs during the first half of April.

In Minnesota, no weather stations reported measurable snow during the month of April. This was the first time that had occurred since modern records begain in 1891 and followed a very quiet March.

The warm and dry conditions led to early fieldwork and planting as well. In Iowa, 68% of the corn was in the ground by April 25th while the 5-year average is only 23%. Minnesota farmers got 63% of their corn planted (5-year avg. of 16%).

8. July Northeast Iowa Flooding (Oelwein)

July 2010 is a month many Oelwein, Iowa (Fayette County) residents will not soon forget. Two rounds of very heavy rain during the month led to devastating flooding in parts of northeast Iowa.

photo of standing water in Oelwein, IA July 7 2010

Slow moving thunderstorms produced very heavy rain during the early morning hours of July 7th. Numerous streets and county roads became impassable with many basements flooded. Rainfall totals that morning ranged from 3.20" to 5.80" around the city of Oelwein with an estimated $400,000 of damage. These rains also caused area rivers across northeast Iowa to rise above flood stage for a short period. (Image left shows standing water from July 7th rainfall in Oelwein, IA.)

On July 22-23rd, 10.15" of rain fell at Oelwein causing yet another round of significant flooding, including more damage to area homes and road closures. Rainfall at Strawberry Point, IA (Clayton County) totaled 9.04" during this round. Numerous rainfall records were set across the Midwest during this period. Several impacted counties were included in Presidental Disaster declarations.

For a more detailed summary of the July 22-24, 2010 event, click here: http://www.crh.noaa.gov/arx/?n=jul2410


Rainfall departure from normal for July 1-10, 2010. (Click on image to enlarge)	Rainfall from July 21-24, 2010. (Click on image to enlarge)

7-day rainfall estimates ending July 24, 2010. (Click on image to enlarge)	7-day precipitation percent of mean July 18-24, 2010. (Click on image to enlarge)

7. July 14 Severe Weather

Heat indicies near 110 deg F helped fuel a line of severe thunderstorms that led to wind damage across southeast Minnesota including a gust of 59 mph at Austin, MN. As the storms moved into western Wisconsin, they produced more wind damage and a long-lived tornado that skipped across parts of Jackson and Clark Counties lasting nearly 30 miles. The EF1 tornado hit rural, wooded areas including the Lake Arbutus resort area between Black River Falls and Neillsville, WI during the late afternoon hours.

For a more detailed summary of the July 14, 2010 event, click here: http://www.crh.noaa.gov/arx/?n=jul1410

6. August 13 Severe Weather

During the late afternoon and evening hours of August 13th, a series of thunderstorms kept redeveloping along an air mass boundary leading to multiple supercells, numerous tornado warnings, and at least two small tornadoes. One tornado near Hayfield, MN (Dodge County) tracked about 5 miles straight north from Hayfield and was ranked EF1. The second tornado touched down briefly in an open field in far southwest Olmsted County, MN.

tornado photo from August 13 2010 near Hayfield, MN

There was also other wind damage and flash flooding as these storms tracked into western Wisconsin. Numerous mudslides were reported leading to road closures and infrastructure damage totaling nearly $3 million. Many rivers rose to minor to moderate flood stage in western Wisconsin.

For a more detailed summary of the August 13, 2010 event, click here: http://www.crh.noaa.gov/arx/?n=aug1310

5. Wet, Warm, and Humid Summer

Through much of the 2010 meteorological summer (June 1st through August 31st), northeast Iowa, southeast Minnesota, and western Wisconsin remained on the periphery of a subtropical high located across the southern United States. While residents underneath this high saw record heat, a progressive train of systems rotating around this high have brought frequent rounds of precipitation across the Northern Plains, Upper Mississippi River Valley, and Great Lakes. With the exception of northeast Wisconsin and western Upper Michigan, the rain has alleviated much of the drought across the region. During the summer of 2010, area rainfall values have generally ranged between 15 and 27 inches. Normally only 13 inches falls during an entire meteorological summer.

The following locations established new precipitation during the summer of 2010...

Location	Summer Rainfall	Previous Record (Year)
Alma Dam 4, WI	24.47"	23.72" (1998)
Hillsboro, WI	22.90"	22.38" (1980)
La Crosse, WI	20.93"	20.32" (2007)
Lone Rock, WI	22.69"	21.93" (2007)
Necedah 2SE, WI	21.80"	20.99" (1980)
Ontario, WI	24.59"	22.68" (2007)
Wabasha, MN	24.21"	22.21" (1993)
Winona Dam 5A, MN	20.21"	20.19" (1998)

Besides being wet, it was also on the warm side. Temperatures averaged 1 to 3 degrees above normal across northeast Iowa, southeast Minnesota, and western Wisconsin. However many would be surprised that the maximum temperatures were anywhere from a degree below normal to 2 degrees above normal. The combination of wet soils and more cloud cover due to the frequent bouts of precipitation kept the maximum temperatures cooler. Meanwhile the minimum temperatures averaged 3 to 5 degrees above normal. This is mainly due to the higher dew points, above-normal precipitation, and cloud cover.

During the summer, Rochester established a new record for daily average dew points (63.1 degrees). This surpassed 62.8 degrees set back in 1995. La Crosse had their second highest average dew points (63.9 degrees). The only summer which had a higher average dew point was 1995 when the average dew point was 64.3 degrees.

4. October 26-27 High Wind

An area of low pressure moved across Minnesota and produced two days of unusually high wind and widespread related damage. Power lines were blown down along with sporadic damage to trees and roofs. This same storm set pressure records in Minnesota (Bigfork, MN - 955.2 mb/28.21") and Wisconsin (Superior, WI - 961.3 mb/28.39") but the pressure gradients were not quite as strong as the high wind event from November 1998. (Image on right is surface pressure map from October 26, 2010 - Click on image to enlarge)

Here are some of the highest peak wind gusts from the 2-day wind storm:

Location	Wind Gust	Time / Date	Source
Stacyville, IA 3E	88 mph	Oct.27	Wind Turbine (262 ft)
Mt.Sterling, WI	70 mph	518 p.m. Oct.27	Amateur Radio
La Crosse, WI 4SE	69 mph	820 p.m. Oct.26	Public
Prairie du Chien, WI 10NNE	64 mph	220 p.m. Oct.26	Law Enforcement
Spring Valley, MN 3E	64 mph	1014 a.m. Oct.27	Public/COOP
Eyota, MN 2SE	63 mph	421 a.m. Oct.27	Road Weather
Union, WI 2S	63 mph	220 p.m. Oct.27	Public
Necedah, WI 1WNW	62 mph	1248 p.m. Oct.27	Fire Weather
Arcadia, WI 2S	61 mph	607 a.m. Oct.27	Road Weather
Spencer, WI 2SW	60 mph	745 a.m. Oct.27	Public
Harpers Ferry, IA	60 mph	1031 a.m. Oct.27	Amateur Radio
La Crosse, WI AP	59 mph	117 a.m. Oct.27	ASOS
Canton, MN 2ESE	58 mph	1119 a.m. Oct.27	Road Weather
La Crosse, WI 4S	58 mph	225 a.m. Oct.27	Amateur Radio / Spotter
Platteville, WI	58 mph	1255 p.m. Oct.27	AWOS
Rochester, MN AP	58 mph	119 a.m. Oct.27	ASOS
Viroqua, WI	58 mph	215 a.m. Oct.27	AWOS
Dodge Center, MN	56 mph	655 a.m. Oct.27	AWOS
Volk Field, WI	56 mph	255 a.m. Oct.27	ASOS
Ionia, IA 2N	55 mph	926 a.m. Oct.27	Road Weather
Platteville, WI 1W	55 mph	1240 p.m. Oct.27	Public
Boscobel, WI 1ENE	54 mph	1103 a.m. Oct.27	Fire Weather
Charles City, IA	54 mph	1135 a.m. Oct.27	AWOS
La Crosse NWS	54 mph	Oct.27	Weather Station
Medford, WI	54 mph	1155 p.m. Oct.26	AWOS
Winona, MN	54 mph	736 a.m. Oct.27	Emerg. Management
Kellogg, MN 2SSE	53 mph	644 a.m. Oct.27	Road Weather
Decorah, IA 5SE	52 mph	1037 a.m. Oct.27	Road Weather
Lone Rock, WI	52 mph	1025 a.m. Oct.27	ASOS
Mauston, WI 1E	51 mph	608 a.m. Oct.27	Road Weather
Neillsville, WI	50 mph	318 a.m. Oct.27	Public

For a more detailed summary of this event, click here: http://www.crh.noaa.gov/arx/?n=oct2610

3. June 17 Severe Weather / Tornadoes

A record tornado outbreak hit Minnesota on June 17, 2010 (a year exactly from when Austin, MN was hit by a tornado in 2009) killing 3 people and injuring many more. A total of 48 tornadoes were recorded in the state that day. Four tornadoes hit southeast Minnesota and western Wisconsin that day (1 EF0 and 3 EF1s), including one passing through the northwest side of Rochester, MN. There was also widespread wind damage as Supercell thunderstorms transitioned into a damaging squall line right across our area.

Storm reports from June 17, 2010 (Click on image to enlarge)

For a more detailed summary of this event, click here: http://www.crh.noaa.gov/arx/?n=jun1710

2. December 10-12 Blizzard / Winter Storm

A significant winter storm hit the area starting on a Friday evening, December 10th, and lasted until Sunday morning, December 12th. The storm not only produced snowfalls of 15 to 24 inches across parts of southeast Minnesota and western Wisconsin, but glaze ice areas south of there and drifting that led to many road closures in Iowa and Minnesota. Many motorists were stranded from the blizzard conditions, high snowfall rate, high wind, limited visibilities, and impassable roads. This storm was the second largest snow storm in Rochester, MN (16.0”) and led to the snowiest December on record. At La Crosse, it was the 8th highest snowstorm on record.

photo of snow pack after December 10-12 blizzard

Bitter cold wind chills followed the storm. The combination of bitter cold and storm clean up prompted many regional schools to remain closed for two days even though the storm hit on a weekend.

For a more detailed summary of this event, click here: http://www.crh.noaa.gov/arx/?n=dec1110

1. September 22-23 Heavy Rains / Flooding

An usually moist air mass for September led to a major rain storm and significant flooding on September 22nd and 23rd. Especially hardest hit areas included southeast Minnesota and western Wisconsin where 6-8” of rain caused millions of dollars in damage and the evacuations of several towns during the event, including Zumbro Falls, MN and Arcadia, WI. Many of these counties were included in federal disaster declarations. Record or near record crests were set on the Zumbro, Black, and Trempealeau Rivers.

For a more detailed summary of this event, click here: http://www.crh.noaa.gov/arx/?n=sep2310

Links to previous Top 10:

National Weather Service Weather Forecast Office