I love all four seasons in Illinois but I especially like fall. In fact, you could say I’m a falloholic. What’s not to like – the air is cool and crisp and the cloud formations are spectacular. One of the best things about fall is the changing color in the trees, shrubs, and grass.
Henry Garnet’s Sweetspire in the author’s front yard.
A great website for all things related to fall color is the University of Illinois Extension site called “The Miracle of Fall“. Check it out for fall color, foliage updates, photos, festivals, etc. You can also find out about fall activities in Illinois at the Office of Tourism site “EnjoyIllinois.com“. A few other sites to explore are:
One of things I get asked every year at this time is, “what is the effect of weather on this year’s fall color?” It’s hard to answer because there is no formula for this. In general, you don’t want drought conditions because the leaves just turn brown and fall off. Instead, you want nights to be cool but not freezing to trigger the change in leaves. Also, you want mild day time temperatures (not too hot) and sunny weather to really make the colors pop.
I hope you take time to enjoy fall in Illinois. I know I will.
The U.S. Drought Monitor has reduced the area in drought for Illinois (first map below). Generous rainfall in recent weeks (second map) along the northern and southern borders of the drought led to the reductions. It also helps that cooler temperatures and maturing field crops have reduced the demand on soil moisture.
Soil moisture measurements from a network of sites operated by the Illinois State Water Survey confirmed that soil moisture was recovering by September 28. The table below list the soil moisture at 2, 4, and 8 inches and are a percentage of the water by volume. For example, “24” at 2 inches in Belleville means that the water content of the soil at that point is 24 percent. For most soils in Illinois, values of 30 percent or more mean plenty of soil moisture, values in the 20 percent range are a little dry, and values in the 10 percent range are very dry. The very low values at Kilbourne are typical of the very sandy soil there. They tend to drain very quickly and are only high right after a significant rainfall events.
Location 2 in 4 in 8 in
Belleville 24 28 27
Big Bend 24 29 23
Bondville 17 17 33
Brownstown 24 22 23
Champaign 21 31 32
Carbondale 28 34 32
DeKalb 38 37 38
Dixon Springs 33 36 38
Fairfield 37 34 35
Freeport 36 37 42
Kilbourne 3 4 3
Monmouth 24 30 24
Olney 26 30 32
Peoria 32 35 35
Perry 17 15 18
Springfield 25 23 14
Stelle 32 34 29
St. Charles 33 38 39
Rend Lake 26 39 40
U.S. Drought Monitor results for Illinois, September 27, 2011.
I think we will remember 2011 as a year of extreme events. In Illinois we have already faced a February blizzard, flooding, record rainfalls, drought, and a heat wave. The latest newsletter of the NOAA’s Regional Climate Centers Program has highlighted several major events from around the country, including:
spring flooding in the Midwest
record flooding in the Missouri River Basin
Check it out. I don’t know about anyone else but I’m ready for a quiet fall.
The natural rhythm of soil moisture in Illinois is to be abundant in spring (sometimes to the point of water standing in fields), followed by a prolonged draw-down during the growing season. Historically, soils are usually at their driest at the end of August and early September. However, soil moisture begins to recover in the September/October time frame as the temperatures cool and crops are harvested, even if rains are below average.
We are seeing some recovery in soil moisture now, according to our soil moisture network maintained at the Illinois State Water Survey. Here is the average soil moisture in the top 20 inches, expressed as a percent of what we saw on June 1 when soil moisture was very high. In other words, values near 100% show a near full recovery while values less than 100% need more rain to recover.