The light, powdery snow that began falling across North Texas early Thursday morning turned slickly dangerous by rush hour and beyond, leading to hundreds of accidents across the Dallas region, early school closings and an extremely cautious commute home. Temperatures hovered in the teens and low 20s most of the day, with wind-chill readings in the single digits.

That left a couple of big questions for Friday: Would the roads be dry or icy, and would electric utilities be able to meet the expected demand? If the snow and slush on area roads refreeze overnight rather than evaporating, morning commuters could face problems. Officials at the Rockwall Independent School District canceled classes for Friday because of ice concerns.

And state utility officials said cold temperatures, coupled with limits on electric generating capacity, could overtax the power grid. “With the cold weather that began [Wednesday night], we already saw electric demand close to our winter record,” said Dan Woodfin, director of systems operations for the Electric Reliability Council of Texas. “We are expecting cold weather to continue through [Friday] morning’s high demand period, and some generation capacity has become unavailable due to limitations on natural gas supplies.” ERCOT asked consumers to lower thermostats to a maximum of 68 degrees and avoid using large appliances during peak demand periods.

Swirling snow When snow began falling Thursday morning, each gust of wind sent it swirling. But commuter traffic led to melting and freezing. And as the bands of snow slid farther south through the day, so did the accident reports, with overpasses and bridges icing along Interstates 20 and 35E, the LBJ Freeway and U.S. Highway 75 through the afternoon, according to the Texas Department of Transportation.

“Please only go out if you absolutely have to,” said Ryan LaFontaine, a TxDOT spokesman. Though road conditions were improving Thursday night, TxDOT crews were set to work 12-hour shifts through the night to tackle icy patches. Municipal crews worked steadily throughout the day to keep busy intersections ice-free. Dallas went to “Ice Force Level 1” about 9 a.m. and later bumped that to Level 2, with 70 sand trucks patrolling the city.

State highway crews spread sand and de-icing materials on bridges and overpasses, but extremely cold temperatures that peaked in the mid-20s made the work a challenge. Even roads and highways that appeared clear of ice and snow could have icy patches, said Tony Hartzel of TxDOT, who watched a truck spin out in his rearview mirror on a seemingly ice-free Interstate 30. And if one vehicle lost traction, others quickly followed. When the driver of a blue sedan lost control on Interstate 35E west of downtown Dallas, slicing across four lanes of traffic before slamming into a guardrail, other vehicles that came upon the crash skidded as they veered around the damaged car.

Police departments reported hundreds of accidents, and damaged cars and trucks littered highway shoulders across the region. By 7 p.m., Dallas police said they had responded to 406 minor wrecks, 146 injury wrecks and 125 injury wrecks on freeways. DART going By midday, with snow still falling, road conditions were bad enough that dozens of area schools decided to close early so children could return home long before the evening commute began. “The Dallas schools have no afternoon or evening activities, and more are closing early, and that will help,” Hartzel said Thursday. “It spreads out the anticipated load on the roads.”

The snow had little effect on Dallas Area Rapid Transit’s light rail service, far different than the complete shutdown it experienced during an ice storm in early December. On Thursday morning, DART officials were at Dallas/Fort Worth International Airport, where an inch of snow fell, giving a Federal Transit Authority official a tour of a train station that will open in Terminal A later this year. DART president and executive director Gary Thomas said he didn’t expect the snow to interrupt service.

“Snow does not,” he said. “Ice is a little problem.” But the snow did affect the airport. Hundreds of flights were canceled, and others were delayed as planes waited to be de-iced at the gates. “The stuff that should be leaving isn’t leaving quite as quickly because of the de-icing,” airport spokesman David Magana said. By early evening, more than 400 flights had been canceled and about 750 had been delayed, according to data from flightaware.com.