ST. LOUIS -- Tens of thousands were without power and the governor declared a state of emergency in the wake of an ice storm that glazed roads and snapped power lines as it moved across Missouri on Sunday.

Gov. Matt Blunt also activated state emergency operations and the Missouri National Guard to aid communities affected by a storm that was expected to continue through midweek.

At Kansas City International Airport, about two dozen flights had been canceled by mid-afternoon Sunday. At Lambert International Airport in St. Louis, 13 flights were canceled.

The brunt of the storm hit central, southwest and northeast Missouri, where utilities reported tens of thousands without power. The storm developed when a cold boundary collided with moisture from the Pacific and Gulf of Mexico.

AmerenUE in St. Louis reported a total of 42,492 power outages in St. Charles, Lincoln, and Warren counties in eastern Missouri, as well as the Jefferson City area, where ice-laden trees were falling down.

About 40,000 Empire Electric customers had lost power, primarily in the Joplin, Webb City and Bolivar areas.

St. Clair County in west central Missouri reported outages countywide, including in Collins and Osceola.

"The rural roads are pretty rough, the main highways are pretty clear, and the overpasses are slick," said John Christiansen, St. Clair County's emergency management director.

Susie Stonner with the State Emergency Management Agency said Missouri was hit by two storm systems that dropped sleet and freezing rain.

One storm moved east across the state from Kansas City; a second one traveled northeast from Springfield up the Interstate 44 corridor.

Another storm was expected tonight into Tuesday, but was expected to clear out by Wednesday, National Weather Service meteorologist Benjamin Sipprell said. Communities reported ice as much as three-quarters of an inch thick, he said.

The state Emergency Management Agency said the worst part of the storm is along the U.S. 54 corridor from the Missouri towns of Nevada to Louisiana. No deaths have been reported, but a Lamar man was injured when a tree fell on him.