The Christmas Day snow has moved out of North Texas, but dropping temperatures brought icy road conditions.
Road conditions quickly began to deteriorate in Fort Worth as night fell. Icy slush on the roads began to harden by 6 p.m., and MedStar said it responded to 71 crashes between 5 p.m. and 9:50 p.m.
Numerous other crashes were reported throughout the Metroplex, and a number of roads and overpasses were closed because of ice or crashes.
Drivers can call the Texas Department of Transportation's highway conditions hotline at 800-452-9292 to hear about road conditions throughout the state.
Dallas emergency crews have been monitoring roads throughout the day. Sand trucks were moving out by 5:30 p.m.
The city's Department of Street Services activated Ice Force 1, which consists of 30 sanding trucks, at 3 p.m. Tuesday. The first shift will run from 3 p.m. to midnight, and the second shift will come in at 11:30 p.m. and stay until noon Wednesday.
Drivers are encouraged to call 311 if they come upon a slick spot so the street crews can respond.
In Fort Worth, trucks fitted with sand spreaders began sanding operations at 4:30 p.m., mainly on bridges and overpasses. Thirty trucks have been on call since Monday.
Fort Worth had two or three trucks patrolling for problems spots Tuesday. If crews find conditions worsening, they will start working 12-hour shifts.
In Collin County, the snow and ice on the Dallas North Tollway overpasses at State Highway 121 began to harden by 6 p.m.
Texas Department of Transportation
The Texas Department of Transportation in Dallas has activated its Emergency Operations Center.
Crews in Collin and Denton counties have found some icing on roads. Those roads are being treated.
TxDOT oversees seven counties that make up its district. The overnight crews have been called in to begin checking equipment.
Bridges and overpasses are the first concern because they are the first to freeze.
The weather conditions that lead to icing include a drop in temperatures, along with the winds picking up. TxDOT believes we could see more icing.
North Texas Tollway Authority
The North Texas Tollway Authority said maintenance crews started patrolling the roadways at 10 a.m. They are using sensors to measure pavement temperatures and conditions on the roads, bridges and ramps.
If freezing conditions develop, the NTTA said it would dispatch crews to sand, plow or de-ice roads. The NTTA has 2,000 tons of MD-20 de-icer and 12,000 tons of sand on standby.
If needed, crews will work 12-hours shifts until the weather event is over.
Travel Trouble in Oklahoma
In Oklahoma, authorities warned would-be travelers to stay home Tuesday as freezing rain and sleet caused a 21-vehicle pileup on Interstate 40 in Oklahoma City on Tuesday morning.
Highway Patrol Trooper Betsy Randolph said several people were taken to hospitals, but she didn't have details on their injuries or conditions.
As of 9:02 p.m., Oncor Electric Delivery reported more than 2,300 customers were without power in the four major counties in North Texas.
The vast majority of the outages were in Dallas County, which had 1,651 outages.
NBC 5's Ray Villeda and Scott Gordon contributed to this report.