Nebraska is in the midst of its driest year on record — drier than any during the Dust Bowl.
Conditions aren't much better in surrounding states where many, including Iowa, have seen one of their driest years dating to 1895.
But what has been remarkably absent this year has been dust storms. Mid-October brought a bad one that stretched from the Wyoming-Nebraska border into Oklahoma.
Improvements in farming get a lot of credit. Absent those improvements, what kind of dust storms would we be having this year?
Not an easy question to answer, said Michael Strobel, director of the National Water and Climate Center for the Natural Resources Conservation Service of the USDA. Even though this single year in Nebraska has been drier than any single year during the Dust Bowl, that era had been years in the making, he said. And those cumulative stresses can take a greater toll.
Jan Curtis, a climatologist at the center, said the cumulative effect of years of drought affects both the surface and deeper layers of soil.
“The longer the drought lasts, the more vulnerable the surface is from wear and tear, whether it's human activity or the fact that the winds pick (dust) up,” he said.
Unrelenting drought, he said, saps moisture from deep in the soil. Even with precipitation, this deep soil moisture has to be replenished for the surface layers to recover. And that's not as simple as a rainfall because a parched surface will resist absorbing water.
Hypothetical comparisons to the Dust Bowl are made tougher by a lack of raw data from that era, Strobel said.
Soil moisture monitoring systems date only to the 1990s and still are fairly sparse. Strobel said researchers have modeled past soil conditions using data for precipitation and temperature and, when available, other weather measurements. Since these aren't actual measurements, it's not clear how dry the soils were then, compared to this year.
This year's dust storm that made news occurred Oct. 18 largely because it caused Interstate accidents in Wyoming, Nebraska and Oklahoma. Nearly three dozen cars and semis were involved in an Interstate 35 pileup in Oklahoma that left nine people injured.
The conditions surrounding that dust storm provide clues to factors that create those long-traveling clouds of earth.
» Strong winds. Oct. 17 and Oct. 18 saw consecutive days of much stronger than normal winds, both sustained and gusts. On the second and worst day, sustained wind speeds reached 35 to 45 mph in central Nebraska, for example, with gusts of 50 mph and 65 mph. In some areas of Nebraska, gusts exceeded 70 mph.
» Recently exposed farm ground. The wind storm occurred at a time of year in which farmers were planting winter wheat. The Oklahoma pileup occurred near a recently tilled winter wheat field. Visibility on I-35 in that area dropped to 10 feet, according to the National Weather Service.
The importance of farm ground in creating dust storms was also evidenced by the track of that dust storm. Even though more powerful winds scoured the Plains north of Nebraska, the dust didn't kick up until those winds reached farm country. An 81 mph wind gust was recorded in South Dakota that day, but the dust storm, based on satellite images, originated along the Nebraska-Wyoming border.
How warm and dry has this year been (keeping in mind that rankings could change by year's end)?
» Driest year to date, averaging 11.92 inches of moisture statewide, which is 9.4 inches short of the 20th century average.
» Second warmest year to date, with an average temperature of 56.2 degrees, 4 degrees above the 20th century average.
» Here's how that compares to the Dust Bowl year of 1934. The average temperature of January-October 1934, was .1 degree above this year's. Total precipitation through October was nearly an inch greater in 1934 than this year — .93 inches more, making 1934 the second driest year to date behind 2012.
» Warmest year to date, with an average temperature of 55.5 degrees, 4.2 degrees above normal. Next in line for year to date was 1921, with an average temperature of .1 degree lower.
» Seventh driest to date, with an average of 22.8 inches of moisture, 6.56 below the 20th century average for this point in the year. The driest January-October on record in Iowa was 1988, when only 18.21 inches had fallen, on average.
Nationwide, this is the warmest year to date for the lower 48 states and 16th driest.
Sources: National Climate Data Center, National Weather Service, National Water and Climate Center for the Natural Resources Conservation Service of the USDA, World-Herald archives.