TULSA, Oklahoma - Freezing rain and sleet across northeastern Oklahoma made for slick driving conditions Thursday morning.

The National Weather Service expanded its Winter Weather warning to include most of northeastern Oklahoma.

The freezing precipitation caused school districts across northern Oklahoma and southeast Kansas to close Thursday.

The Oklahoma Department of Transportation had crews out and continued to spread sand and salt on highway bridges.

ODOT encouraged drivers to slow down and allow extra time during their morning commute.

In Tulsa, EMSA says it responded to 6 crashes between 5 and 9 a.m. It says 5 patients were transported to local hospitals. None were in serious or critical condition.

There is also a power outages reported in Creek and Washington counties, that may be due to the weather.  OG&E says 1,339 Sapulpa customers are without power as of 7:15 a.m.  Verdigris Valley Electric has about 500 customers near Bartlesville without power as of 7:30 a.m.