Foothill Grasslands

Severe drought now covers nearly nine-tenths of El Paso County, and it got there in about six weeks. In the second week of June the U.S. Drought Monitor had none of the county in severe drought or worse. By mid-June 12 percent was. By the first week of July it was 58 percent, by the end of July 93 percent, and by the middle of August 97 percent. Extreme drought, the next category up, went from none at the end of June to 65 percent of the county in the week of August 11.The latest map, for the week of September 8, puts 90 percent of the county in severe drought or worse and 40 percent in extreme drought. The retreat of the extreme category since mid-August is the only movement toward wet. County-wide August rain came to about 2.1 inches, half an inch under the 1901-2000 average, enough to pull part of the county back from extreme to severe but not enough to move the severe line. September has added nothing. Colorado Springs Municipal Airport, 12 kilometers from the grasslands, has measured no precipitation this month against a normal of 0.63 inches, and its average daily high over the past 30 days was 86.9 degrees, 7.4 degrees above the 1991-2020 normal for those dates.The timing lands on the grasses that define this ground. Blue grama, sideoats grama, big bluestem and little bluestem are all recorded across Bluestem Prairie Open Space, and all four are warm-season grasses that flower and fill seed from July into September. The drought set in during the first week of July, at the start of that window. These grasses answer dry soil by letting the leaves brown and drawing sugars and nitrogen down into the crown and roots, where the buds for next year's tillers sit. Seed heads that had already started can finish on stored reserves. New tillers and root growth stall. Blue grama's production on the shortgrass steppe tracks growing-season rainfall far more than temperature, so a summer that turned dry in early July is a summer of short growth no matter how warm it ran.From the trail this reads as a prairie that cured early. Warm-season grasses brown every fall, and this year the drought pushed that turn ahead of the calendar. The open question is next spring. Regrowth after rain comes slower where the crown reserves were spent getting through the dry spell, and how much of that happened here depends on what falls between now and the first hard freeze.