Climate

Marvin Stone, Ph.D.
Department of Geography
University of Nebraska at Kearney

Appraising the climate of the Big Bend is more than the recitation of statistics. Any evaluation is clothed in the reactions of the region's inhabitants, who express various sentiments about their encounters with the elements. The authors of books about Nebraska have produced the following: "Nebraska often experiences sudden changes in temperature," the mildest of the comments. Another writer says, "Nebraska's climate is violent." Still another states, "Winter temperatures are quite low; summers are exceptionally hot." (A counter comment might have been that winters are exceptionally cold.) On safer ground, one writer remarks, "If there is any word which best describes Nebraska's climate, it is unpredictable." It is difficult, it seems, to be neutral and objective about climate when it so strongly affects one's well-being.

The land lies in a zone where rainfall diminishes rather rapidly westward. Across the state the average annual precipitation declines about one inch for each twenty-two miles. In the Big Bend region, the range is from twenty-six inches on the eastern edge to eighteen inches in the west. Rainfall is concentrated in the warm months, peaking in June, and falling primarily at night.

These are averages, however, only to be interpreted in a general way. Some precipitation does come in "storms." "Unpredictability" is an accurate descriptor. Quality of precipitation--whether too heavy or too light to be useful or whether at the right time to be useful--is significant. The record shows that Kearney's wettest month was June, 1967, in which 15.14 inches of rain fell. This was more precipitation than the whole year of 1940 received, which was the record low of 11.65 inches. The greatest single rainfall occurrence was 6.87 inches on June 24-25, 1989. (A light frost also occurred in June, 1989 on the 15th!) The greatest annual precipitation was 40.07 inches in 1915.

Lying near the middle of the continent, central Nebraska experiences the extremes of temperature characteristic of continental climates. The terminology blandly attached to these climates is "hot summers-cold winters." This catch-phrase, however, is inadequate to comprehend the variability in short term weather occurrences where the "average" temperature or the "average" precipitation for the period is missed widely. It is common to experience "spells" that are warmer or colder, wetter or drier than the season is expected to justify. The movement of air masses, with cold or warm fronts, causes frequent weather changes. Guided by the high altitude jet stream that marks the boundary between these air masses, cyclonic storms often provide precipitation occurrences along the fronts.

Cold fronts penetrate the region more than twice as often in winter as in summer, producing more frequent temperature and wind changes. The very cold air masses which occasionally move through the area in winter may lower temperatures rapidly. Declines of fifty degrees Fahrenheit in a twelve-hour period have occurred in late winter when warming of the land is interrupted by air flows from the frigid land to the north. Typical winter temperatures will include several days with temperatures dropping below zero (F). How many days? It could be three or three dozen. Temperatures even in mid-winter, however, can rise above sixty degrees, allowing for a winter range commonly exceeding seventy-five degrees for a single winter. Mid-summer temperature ranges, on the other hand, seldom exceed sixty degrees. However, hot mid-summer temperatures may be very persistent in some years, lasting for several weeks.

It is difficult to imagine a more dreadful year than 1936 for Big Bend residents. In the midst of a drought already in its fourth year and a numbing economic depression, the year set all-time records for severe cold in February and for extreme heat in July. Blizzards occurred in February. Temperatures that month frequently dropped far below zero, as much as twenty-one below. Grand Island recorded the following extremes:

   Degrees Fahrenheit
   Feb.  9  -21   Feb. 18  -17
   Feb. 14  -20   Feb. 19  -16
Five months later the temperatures reached or exceeded one hundred degrees for twenty-two days in Grand Island, the maximum being a record 117 degrees on July 24. On eight occasions temperatures reached 109 degrees or greater:

   Degrees Fahrenheit
   July 3   110   July 17  114   July 25  116
   July 4   109   July 18  111   July 26  111
   July 16  111
Kearney reached an extreme of 114 degrees. The wind blew mercilessly in the spring and summer of that year, and grasshoppers arrived in droves. The crops were chewed up or withered away in the heat and the wind. Not surprisingly, the hardship of the "dirty thirties" intensified in 1936. The drought and its attendant miseries did not end until 1941.

In a region where the people's livelihood is often influenced by weather conditions, weather is watched carefully. Even as the quality of forecasting and media reporting has improved over the years, the need for information has not diminished. On the farm, livestock and tillage management rely on accurate information. It is the extreme weather, in particular, that threatens danger and economic loss. A prototype of the Great Plains, the Big Bend region has tornadoes, blizzards, wind, hail, and ice storms. Tornado frequency increases from west to east paralleling rainfall increase. Hail incidence increases in the opposite direction. West central Nebraska experiences an average of four days of hail per year while the Panhandle averages six hail days.

Sometimes an individual blizzard or a winter of many blizzards, such as in 1948-49, devastate cattle herds, but the less dramatic routine deviations in rain, snow, wind, heat, and cold that are a part of continental climates cause more total livestock losses over time.

Loss of human life due to weather is not common. People have adapted; the variability of the weather is more typically an inconvenience rather than a major problem.

With an improved science regarding weather and climate comes an awareness of potential problems. None can be more direct to an agricultural state than the threat of global warming. Some scientists propose that man's destruction of the world's forests coupled with burning of fossil fuels contribute to an increase in carbon dioxide in the atmosphere.

Increased carbon dioxide causes absorption in the atmosphere of the earth's radiation, in turn increasing air temperatures. Increased heating can pose a threat to crops that already must tolerate the many high temperatures occurring in summer.

Perhaps a greater threat related to global warming would be the possibility that the storm track would move northward as the general circulation of the atmosphere responds to heat-induced pressure change. The threat to the Big Bend region would be more frequent drought, a prospect which has serious economic implications.

While the region relies on irrigation to mitigate the damage of a drought, increased pressures upon the water resources may not bring about a response adequate to the need. Observers and scientists watch with great interest the evidences of climate change. The implications are important.

Suggested Reading: Lawson, M. P. 1977. Climatic atlas of Nebraska. Lincoln: Univ. of Nebraska Press.