Mississippi officials said they were sending 135 snowplows Wednesday to clear ice and snow from two interstate highways where frozen conditions caused huge traffic jams. The Mississippi National Guard said citizen-soldiers equipped with wreckers began arriving before dawn to help clear I-55 and I-22. Roadside cameras operated by the Mississippi Department of Transportation showed semitrucks and pickups bumper-to-bumper on stretches of I-22 lined with snow. The Mississippi National Guard said citizen-soldiers equipped with wreckers began arriving before dawn to help clear I-55 and I-22. More than 380,000 homes and businesses, most of them in Mississippi and Tennessee, remained without electricity, according to the outage tracking website poweroutage.us.