A few weeks ago, very strong winds blowing dust across a south-central Illinois highway suddenly reduced visibility to just a few feet and resulted in a tragic, fatal multicar pileup. While extremely strong winds don’t occur often, it does seem like this spring in Illinois has been windier than usual.
Wind is caused by air moving to equalize differences in air pressure. Air pressure is the force exerted due to the mass or weight of air. These differences are generally not great, but the greater the difference in pressure, and the closer the differences are, the faster the wind will move.
One rhyme to remember is “air will blow from high to low.” In other words, air moves away from high air pressure to areas of lower air pressure. The other general weather rule is that low pressure is associated with clouds and storms, while high pressure is associated with fair weather.
Spring is normally a time of faster wind speeds in the Midwest. The jet stream is the driver of mid-latitude cyclones. Mid-latitude cyclones is the long name for low-pressure areas, and these are the L’s or you see on a weather map. The jet stream is often located over the Midwest this time of year, moving in a wavy fashion from west to east. As the jet stream waves move, that brings about changes in air pressure, and winds associated with those changes.
Multiple reports throughout the Midwest and the Great Plains have indicated this has been a windier spring than average. The jet stream has been very wavy the past few months, and the bigger the wave is, the stormier it can be, depending on where the wave is at.
Studies seem to be showing winds in general have trended stronger over the last 10 to 20 years. However, in future decades, winds may become slower, according to some climate scenarios.
Today, dust storms don’t occur very often in Illinois, but with the windier conditions we have had this spring, some areas have seen soil in the top few inches dry out, making it easier for winds to pick up soil particles. Back in the days of plowing, dust storms were fairly common this time of year.
Right after the last Ice Age ended about 10,000 to 14,000 years ago, huge long-lasting dust storms covered much of the central Midwest. Large amounts of sediment had been deposited in the Illinois and Mississippi River valleys from torrential floods from the ice melt. When the sediment dried out, this fine, floury textured material, called loess, blew out from the river valleys. Dunes 25 feet or higher next to the river valleys were created. Blowing out for hundreds of miles, more distant areas were covered with 2 to 4 feet of this material. After several more millennia, this wind-blown loess became the incredibly productive prairie soil we have today.
Duane Friend is Illinois Master Naturalist Coordinator and Climate Specialist, University of Illinois Extension.