(AP) Snow fell across parts of Oklahoma and the Texas Panhandle on Monday, part of a storm system that produced at least two weekend tornadoes and hail as big as softballs.

The National Weather Service posted a snow and blowing snow advisory for parts of Oklahoma, with 3 to 6 inches possible in eastern sections Monday. In the Texas Panhandle, ice and snow covered local roads in western areas of the Panhandle but no problems were reported.

On Sunday, two tornadoes were spotted in rural areas of northwestern Oklahoma. Television footage showed one twister passing the communities of Carleton and Southard in northern Blaine County.

No fatalities or severe damage were reported, but downed power lines caused scattered blackouts. The Oklahoma Highway Patrol said one highway near the Kansas state line remained closed Monday because of fallen power lines.

"It was just more of a scare than anything else, really," said Blaine County Sheriff's Deputy Adam Austin.

The storm system also produced wind gusting up to 70 mph, lightning and hail as large as softballs that caused scattered damage, said weather service meteorologist Chris Sohl in Norman.

Such a storm system "is not all that odd, but this early in March sometimes it's a trick to get enough moisture up here for (atmospheric) instability," Sohl said.

The stormy weather formed along a cold front stretching across the middle of the nation. Radar showed rain falling along the front from Texas to Michigan on Monday morning with snow in parts of Michigan and Wisconsin.

Elsewhere, blizzard conditions and accidents in Colorado on Sunday closed Interstate 70 from Limon to the Kansas line for part of the day, with similar conditions reported on Interstate 25 south of Denver. Blowing snow hit most of Colorado, with the weather service reporting 15 inches of snow in the mountains west of Denver.