The U.S. Midwest and Plains remain in a deep freeze on Tuesday morning, with sub zero temperatures at record or near-record lows, raising the risk of winter-kill damage to dormant wheat along the Ohio River valley, meteorologists said.
Overnight lows fell to -5 to -10 degrees Fahrenheit (-20 to -23 Celsius) across southern Indiana, Ohio, Illinois and northern Kentucky - big soft red winter wheat country, where much of the area was unprotected by snow cover.
"It was cold enough to put about 5 percent of the soft wheat crop at risk," Joel Widenor, an agricultural meteorologist with Commodity Weather Group, told Reuters.
Snow cover protects dormant wheat when temperatures dip below zero and persist for four hours or more. Without sufficient snow cover, damage to exposed wheat can prevent the crop from reaching its full yield potential next summer.
The central Plains hard red winter country was warmer early Tuesday, with lows in the single digits up to the 20s F, a big contrast from the -10 to -20 F readings on Monday, when up to 30 percent of the Plains wheat belt was at risk of winter kill, agricultural meteorologists said.
The frigid temperatures and weekend snows also slowed livestock and grain shipments through the heartland and curbed meat production and several packing plants.
The Illinois River, a major artery to ship grain, was open to barge traffic on Monday but ice buildup created bottlenecks along a slow-moving stretch of the river near Peoria.
The upper Midwest remained in a deep freeze early Tuesday, with temperatures falling to the minus teens F and wind chills of -35 to -40 F.
But temperatures will warm into the 20s to 30s F later this week, with some southern Midwest locations possibly seeing highs in the 40s F, according to forecasters.
"Most of the snow came to an end yesterday, so transportation should be improving," said meteorologist Andy Karst with World Weather in Kansas City.
"Another storm is headed to parts of the Midwest Wednesday into Thursday and again on Friday into Saturday - it's not going to be a big deal."