…Drought Comparisons for the Tri-Cities of Grand Island…Kearney and Hastings, Nebraska…
Drought is defined as a period of abnormally dry weather sufficiently long enough to cause a hydrological imbalance. For the Plains States, drought has been a recurring theme throughout the ages, with marked impacts on society tracing back as early as 1280, and more extensively during the past 100 to 150 years. A widespread meteorological network in place across Nebraska during the 1930’s provided the first detailed record of precipitation and temperature, documenting the “Drought of the Ages, ” a severe drought that lasted 10 years across the Central Plains.
While the “Dirty Thirty’s” serves as a measuring stick for present day climate change, other methods of scientific research have revealed more severe drought periods within the past 2000 years. Tree-ring growth studies in western Nebraska show the 1930’s drought was not that uncommon, and the “Dirty Thirty’s” actually pale in comparison to a 38-year drought that began in 1276, and another 26-year drought in the middle 1500’s. For example, from around 300 to 1300, indigenous tribes flourished in Nebraska, growing crops and building permanent earth lodges during a time when the local climate was warm and moist. Shortly after, extreme drought developed over the Central Plains, forcing the tribes to abandon the region.
Similar conditions developed again during the latter half of the 1800’s, and a 9-year drought from 1858 through 1866 forced early homesteaders out of Nebraska. Their departure was short-lived as the Union Pacific built west through Nebraska, bringing a return of people to the region. During this period, a wet weather pattern provided favorable living conditions, and it was heralded that due to the homesteader's exodus in the 1860’s, the decrease in cultivated farmland actually brought the return of increased precipitation.
In 1884, another 12-year drought developed over the Central Plains, compounded by crop failures and an economic depression that lead to another abandonment. Other factors also came into play. Many people brought farming methods from the east that were not suitable for the dry climate of the west, nor did they account for the type of soils, climate and water availability. Conditions were so severe that the health of the settlers suffered. Many were new arrivals that had brought little with them. When the drought and depression struck, malnutrition was common, and starvation took many lives. Though the drought years of the 1880's and 1890's were not as severe as the 1930's, the vulnerability of the settlers made the impacts of drought more disastrous. People were inadequately prepared for such a harsh drought, and even when the moisture returned, the recovery process was extremely slow.
Dry farming techniques were developed and thought to be the solution to the drought problem, and as a result, a new wave of settlers moved into the area in the early 1900's and rode out another 8-year drought from 1905 to 1913.
Simply stated, drought is not that unusual of an occurrence over the Central Plains, and even a minor drought creates societal, agricultural and hydrological hardships. Nebraskans should expect and prepare for long term and/or strong droughts in the future.
The following series of tables and graphs provide a comparison of the present drought to the benchmark drought of the 30’s for the Tri-Cities of Grand Island, Kearney and Hastings, Nebraska. While this comparison is a “thin slice of the pie” over a relatively small area, a more detailed analysis would likely show similar results with some variation to the extremes.
In summary, it is quite obvious that the drought of the 30’s was significantly drier and warmer than the 1999-2006 drought. As with both drought periods, there were individual years that struck harder than others, but a review of annual precipitation shortfalls in the Tri-Cities shows without question the severity of the “Drought of the Ages.”
Note: In order to complete the 2006 calendar year, monthly averages for December were utilized for each city to smooth the 2006 calculations. For statistical continuity, an equal number of years were used from each period. Had the actual 1931 to 1940 drought averages been utilized, the Drought of the 30’s would have indicated slightly drier and warmer conditions.
There were 3 years during the drought period that Grand Island received about half of its average annual precipitation, and only 1 year, 1935, with above normal precipitation. The two warmest years were 1933 and 1934, with 1934 being the hottest and one of the driest. The 112-year average for 100 degrees or warmer days is 7.7 days per year, there were 47 at Grand Island in 1934, with 14 consecutive days prior to July 24, 1934 when maximum temperature was at or above 105 degrees. 1934 was also marked by dry spells. The longest dry spell, and also the longest during the 8-year drought, ended December 22, 1934, after 57 consecutive days without measurable precipitation. Previous to that, the 35 days prior to February 17, 1934 were dry, as were the 28 days prior to May 4, 1934.
While the 30’s had three years with cooler than normal annual temperatures, all years during the recent drought cycle finished above normal but not to the extreme of the warmest years during the 30’s. The average number of days with temperatures at or above 100 degrees was 4.9 days during the 1999-2006 period. 2006 logged in the greatest number of days with 100 degrees or warmer temperatures with 10. There were two years, 2002 and 2003, with significant precipitation shortfalls, and had it not been for the rain from the 100-year flood of May 11-12, 2005, Grand Island and surrounding communities would have likely witnessed an annual precipitation shortfall of around 3 inches in 2005.
When comparing the two droughts, the 30’s “wins” as the warmest and driest. Of the 25 warmest years at Grand Island, 4 of the warmest years occurred during the 30’s cycle and were ranked, the 1st, 3rd, 5th and 19th, with 3 years during the current drought ranked as the 15th, 17th and 20th warmest. What really stands out is the large precipitation deficit during the 30’s, when precipitation was about 75 percent of normal, compared to 89 percent for the recent 8-year period. When comparing percent of normal, Grand Island was the driest of the Tri-Cities by only a few percentage points during the 30’s, and was 6 to 8 percent drier during the recent drought period. The 112-year average number of days with 0.10 inches of rain at Grand Island is, 47.7, the 8-year average in the 30’s was 40.7 and there was an average of 44.1 days during the present drought. Also of note, Grand Island’s recent 8-year drought finished more than a degree warmer than Kearney and Hastings.
Kearney’s moisture shortage hit hard three of the eight years with only around 50 percent of the normal annual precipitation measured. While two years ended with above normal precipitation, the surpluses were minimal. The 113-year average number of days annually with precipitation a tenth of an inch or more at Kearney is 45.9 days, just a little bit better than Grand Island’s. The years with the least number of days with a tenth of an inch or more were 32, in 1934 and again in 1936. There were 40 days with maximum temperatures at or above 100 degrees at Kearney in 1934, compared to the 113-year annual average 6.4 days.
The current drought in Kearney, like Grand Island and Hastings, did not initialize until the fall of 1999. While it is apparent that 2002 and 2003 were the years with extreme precipitation deficits, other years suffered extended dry spells, usually from late winter through mid summer with infrequent periods of heavy precipitation. But again, while annual precipitation totals may appear to be normal or significantly above normal, record rainfall in 2005 during the late spring, and frequent rain in the late summer and fall of 2006 masked the extended dry periods that occurred both years. For the most part, there were no years of exceptional warmth. The 113-year annual average number of days at or above 100 degrees is 6.4 days, and during the 1999-2006 period the average was 2.9 days. The year with the greatest number of days at or above 100 degrees between 1999-2006 was 6 days, in 2003 and 2005.
When comparing Kearney’s 8-year averages for both periods, the 30’s drought was the obvious leader at Kearney in both the temperature and precipitation categories. The 8-year average annual temperature was about a degree-and-a-half warmer in the 30’s than during the recent drought period. Percent of normal precipitation for the 8-year period of the 30’s drought fell short by 25 percent, compared to 3 percent for the 1999-2006 period. The 113-year average number of days with temperatures at or above 100 degrees is 6.4 days, and compares to 19.6 days in the 30’s, and 2.9 days during the recent 8-year period.
Temperature and precipitation data for Hastings were missing for several months between 1936 and 1938. For those months, values were smoothed using the 113-year average monthly values for the missing months. Based on these averages, trends similar to Grand Island and Kearney were recognized, and temperatures averaged warmer than the measured averages at Kearney and Grand Island. The smoothed 113-year average for Hastings showed an average 8.1 days per year with temperatures at or above 100 degrees. The 8-year period in the 30’s averaged 29.9 days per year with temperatures at or above 100 degrees, with 1936 having the most at 55 days. Precipitation trends also mirrored Grand Island and Kearney, but more precipitation was evidenced by an annual average of 41.4 days per year with precipitation measuring 0.10 inches or more, compared to 40.7 days at Grand Island, and 37.6 days at Kearney.
Except for 2000, 2002 and 2003, drought conditions were masked by infrequent periods of rain with the late spring and late summer months being the driest. Average annual temperatures for each year were all within a degree of the 113-year average temperature. Similarly, despite the shortfalls in 2000, and the back-to-back years in 2002 and 2003, half of the period finished with above normal precipitation.
While missing data during the 30’s may skew averages slightly, the months with available data indicate Hastings was the hottest of the Tri-Cities during the 30’s. To substantiate this, Hastings experienced 239 days with temperatures at or above 100 degrees during the 1933 -1940 period, compared to 201 days at Grand Island. The number of days at or above 105 degrees was nearly balanced with 86 days at Grand Island, and 85 days at Hastings. During both drought periods, precipitation in the Hastings area seemed to fare better than Grand Island and Kearney by just a slight margin.