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Serving: IA
2010: 2nd Wettest Year In History

2010: 2nd Wettest Year In History

For temperature, Iowa had a statewide average in 2010 that was about normal for the year. But what goes into the record books is how wet it was, 2010 is second wettest year in the state's history.

Harry Hillaker, state climatologist at the Iowa Department of Agriculture in Des Moines, keeps track of rain, snow and temperatures all year long in Iowa. He puts out a monthly summary at the end of each month, and then a summary for the year. His summary released a few days ago shows 2010 wasn't remarkable for average temperature statewide for the year.

That's because the three winter months of the year—January, February and December 2010—were all well below normal for temperature, and that was enough cold weather to almost cancel out the other 9 months (March through November) which all averaged warmer than normal.

As a result, 2010 averages out to about normal on temperature for Iowa statewide. However, what will go into the record books is how wet it was. The year 2010 is the second wettest year in state history.

Iowa's top 10 weather events for 2010—state summary

Iowans love talking about the weather, and when you have 138 years of weather records at your disposal, you have more to talk about than most folks. The state climatologist's office in Iowa was established in 1875 and is America's oldest continuously operating state climate service. Hillaker, as the current state climatologist, continues to collect, process and publish climate data for hundreds of Iowa weather reporting locations and make it available to the public.

A variety of the records kept by the state climatologist's office can be found on the state ag department's website at  In addition, Hillaker has put together the Iowa weather summary and a list of the 10 top weather stories for 2010 that are included here:

1) Persistent deep snow cover (Dec. 9, 2009 – March 7, 2010): The near-record snowfall of December 2009 and persistent cold weather combined to allow the statewide average snow cover to exceed five inches for an amazing 89 consecutive days. Snow cover exceeded 30 inches over parts of northwest and north central Iowa and sometimes exceeded 20 inches as far south as Lamoni.  Only January 1979 (40°) and December 1983 (40°) recorded lower statewide maximum temperatures than January 2010 (45°) and February 2010 (42°).

2) Frigid start to 2010 (Jan. 1-12, 2010): The new year got off to the coldest start since 1979 with temperatures over the first twelve days of the month averaging 16 degrees below normal. Spencer Airport reported a low temperature of minus 37°F on the morning of the 2nd while Estherville had a wind chill of minus 53°F. Estherville's wind chill was the lowest recorded in Iowa since Feb. 1, 1996.

3) A warm spring (March 6-May 31, 2010): Above normal temperatures were the rule for most of the spring and were a welcome relief from the long snowy winter. A quick succession of 'firsts' for the year included the first 50s (March 8), 60s (March 10), 70s (March 29), 80s (March 30) and almost reached 90° on April 1 (89 at Little Sioux). Overall the spring of 2010 was the warmest since 2000 and 15th warmest among 138 years of records.

4) A record wet June (June 1-27, 2010): Persistent rain fall produced a new record high statewide average precipitation total for the month of June of 10.34 inches. This broke the previous June record of 10.33 inches set in 1947 and was second only to July 1993 (10.50 inches) among all calendar months.

5) Sibley Tornado (June 25, 2010): Following what probably was Iowa's quietest spring severe weather season in over 30 years, a very strong tornado touched down near Little Rock on the evening of June 25. This storm was on the ground for about 14 miles just to the southwest of Little Rock and Sibley and reached an intensity of EF-4. At least 10 injuries were reported from what was Iowa's strongest tornado since the devastating Parkersburg storm of May 25, 2008.

6) Maquoketa River Deluge (July 22-23, 2010): Very heavy rains fell over the entirety of the Maquoketa River basin on the night of July 22 with additional heavy rain the next night. Oelwein reported 9.93 inches of rain on the first night of the storm and another 3.16 inches the next night. The flood surge down the Maquoketa River washed out the Lake Delhi dam and caused millions of dollars in damage along the lakeshore and downstream. Monthly rain totals peaked at 20.33 inches at Oelwein while statewide this ranked as the fifth wettest July among 138 years of records.

7) Central Iowa Downpours (Aug. 8-11, 2010): Very heavy rain fell on three consecutive nights across central Iowa with a total of 9.86 inches of rain at Ankeny. Major flooding resulted in Ames and points downstream along the South Skunk River, as well as in smaller water sheds such as Walnut Creek and Four Mile Creek in the Des Moines area.

8) A Warm and Muggy Summer (June 1-Aug. 31, 2010): Very wet conditions prevented exceptionally high temperatures during the summer of 2010 with Ankeny the hot spot with a statewide maximum temperature of 98° on July 14.  However, persistence made up for lack of extremes as temperatures averaged warmer than normal on all but 24 of the 91 days of summer. The result was Iowa's warmest summer since 1988 and 19th warmest summer among 138 years of records.

9) Perfect Harvest Weather (Sept. 26-Nov. 11, 2010): Unseasonably warm and dry weather made for one of the most rapid harvests on record in Iowa.  Precipitation averaged only 25% of normal from late September through early November while temperatures averaged 3.4° above normal. The 2010 harvest was a huge contrast to last year when Iowa endured its coolest October in 84 years and wettest October since 1881. Virtually all soybeans and 97% of the corn crop were harvested by the end of October 2010 compared to 54% of the soybeans and 18% of the corn last year.

10) December Blizzard (Dec. 11-12, 2010): Very high winds and widespread snow brought blizzard conditions statewide, particularly on the night of the 11th. Snowfall amounts ranged from only an inch or two over the southwest and southeast corners of Iowa while 6 to 10 inch totals were common over the northern two tiers of Iowa counties. Waukon reported the most snow with 12 inches. Wind gusts of 50 to 60 mph were the rule over the western one-half of Iowa and in the 40 to 50 mph range over the east. The statewide average snowfall with this storm was 3.8 inches, thus not nearly as great as the 10.5 inch average of the Dec. 7-9, 2009 event.

Statewide Annual Statistics: The statewide average precipitation for 2010 stands at a preliminary 44.32 inch total through Dec. 22. This ranks second to only 1993 (48.22 inches) among 138 years of statewide records. Greatest totals fell over south central Iowa where some locations saw more than 60 inches of precipitation. Record annual precipitation totals for individual cities were set at locations such as Hawarden, Sanborn, Oelwein, Audubon, Ankeny, Fort Dodge, Grinnell, Indianola, Mount Ayr, Washington and Keokuk. The wet spot in 2010 appears to be Lake Rathbun Dam with 66.72 inches. Only Muscatine's whopping 74.50 inch total in 1851 exceeds 2010's total at Rathbun in the historical record.

The statewide annual temperature could still change depending upon weather over the last half of December but at the moment averages 48.0° or 0.2° above normal. Temperatures were well below normal in the winter months of January, February and December, but above normal for the other nine months of the year.

A total of 33 tornadoes were reported in Iowa in 2010 according to statistics gathered by National Weather Service. This is less than the annual average of 48 tornadoes and only two of this year's storms were rated EF-2 strength or greater.

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