April 2011 Climate Summary

For a printable version of the climate summary which includes more figures, data tables, and state summaries, click here. 

Temperature Summary

Temperatures were generally warmer than normal in the south and cooler than normal in the north across the High Plains Region this month. The majority of Colorado and Kansas were warmer than normal and average temperatures were up to 5.0 degrees F (2.8 degrees C) above normal. While the warmth was not record breaking, the persistent dry weather in western and south-central Kansas has stressed the winter wheat crops and caused them to decline.

Meanwhile, April was the fifth month in a row in which average monthly temperatures were cooler than normal in the Dakotas. Each state had average monthly temperatures which ranged from near-normal to 5.0 degrees F (2.8 degrees C) below normal. In addition, locations in these states generally ranked in the top 25 coolest Aprils on record. The Theodore Roosevelt Airport in Dickinson, North Dakota had its 19th coolest April on record with an average temperature of only 38.8 degrees F (3.8 degrees C) which was 4.0 degrees F (2.2 degrees C) below normal (period of record 1948-2011). The record was set in 1950 with an average temperature of 31.9 degrees F (-0.1 degrees C). The cool, wet weather has delayed or slowed fieldwork and planting in not only the Dakotas, but also in Nebraska. In Wyoming, these conditions have delayed mountain snowmelt and allowed the snowpack to continue to grow. In addition, the snow water equivalency of the snowpack at the end of the month was 154 percent of average. The combination of these factors has raised concerns of flooding in some areas.

Precipitation Summary

When compared to other areas of the country, April was a relatively quiet month and winter still had its grip on much of the High Plains Region. Several systems that moved through the Region brought a wide variety of conditions, including snow, ice, high winds, hail, flooding, and tornadoes. A major system passed through the Region April 14-15. Heavy wet snow and high winds created treacherous blizzard conditions in western Nebraska, eastern Colorado, and northwestern Kansas. Interstate 80 was closed, as were local schools. In addition, several communities lost power. In South Dakota, several locations reported up to a foot (30 cm) of new snowfall and, according to the National Weather Service office in North Platte, Nebraska, snow drifts of 7-10 feet (213-305 cm) occurred with this storm. This same system brought severe weather to central Kansas. Damaging straight line winds, hail as large as tennis balls, and tornadoes were all reported.

By the end of the month many locations in North Dakota had snowfall totals that ranked in the top 10 snowiest Aprils. Bismarck, North Dakota had its 5th snowiest April on record with 13.4 inches (34 cm) (period of record 1886-2011). Bismarck’s record occurred in 1984 with 18.7 inches (47 cm). With 12.6 inches (32 cm) of snow, Williston, North Dakota had its 6th snowiest April on record and pushed its record-breaking seasonal snowfall total up to 107.2 inches (272 cm). Williston’s April record occurred in 1896 with 26.6 inches (68 cm) (period of record 1894-2011). South Dakota’s seasonal snow totals increased this month as well. With an April snowfall of 0.7 inches (2 cm), Sisseton, South Dakota’s seasonal snowfall total came to 82.7 inches (210 cm) which surpassed the old record of 82.3 inches (209 cm) set in the 1993-1994 snow season (period of record 1900-2011).

As expected, flooding did occur along the Red River this month. On the 9th, the Red River crested at Fargo, North Dakota at 38.75 feet which was the 4th highest on record (period of record 1897-2011). The record occurred on March 28, 2009 when the river crested at 40.84 feet. On April 14th, the Red River crested at 49.87 feet at Grand Forks, North Dakota which was the 3rd highest crest on record (period of record 1883-2011). The highest crest on record occurred on April 22, 1997 at 54.35 feet. According to the North Dakota State Climate Office, many roads and parts of the interstate were closed due to the flooding.

Climate Outlook

La Niña conditions were present across the equatorial Pacific this month and a transition to El Niño Southern Oscillation cycle (ENSO)-neutral conditions is expected by June. The temperature outlook indicates a higher probability of above normal temperatures for southern portions of Colorado. North Dakota, South Dakota, eastern Nebraska and far northeastern Wyoming have a higher probability of below normal temperatures. Equal chances of above, near, or below normal temperatures are predicted elsewhere in the Region. The precipitation outlook indicates a higher probability of above normal precipitation for the majority of North Dakota, eastern Kansas, and the southeast corner of Nebraska. Equal chances of above, near, or below normal precipitation are predicted elsewhere in the Region. The seasonal outlooks combine the effects of long-term trends, soil moisture, and when applicable, ENSO.More information about these forecasts can be found here.

Drought Watch

There were some significant changes to the U.S. Drought Monitor over the past month. Generally, drought conditions worsened in Colorado and Kansas and improved in Nebraska and Wyoming. The Dakotas remained drought free. Drought conditions deteriorated along the Kansas-Colorado border where extreme drought conditions (D3) were introduced. Severe drought conditions (D2) also expanded from Oklahoma into south-central Kansas. The state of Nebraska had many improvements over the past month as much needed rainfall helped eliminate the moderate drought conditions (D1) in the south central part of the state and abnormally dry conditions (D0) in the central and eastern portions of the state. D0 was also eliminated in northern Wyoming due to increased precipitation and an above normal snowpack. According to the U.S. Seasonal Drought Outlook released April 21st drought conditions across Colorado and Kansas were expected to persist.