KDFW-TV reported a line of storms moving through North Texas had spawned multiple tornadoes that caused damage to homes, large hail and heavy rains.
The Dallas Morning News reported Granbury officials requested medical help from other counties.
WFAA-TV said the American Red Cross said based on initial reports it believed Hood, Johnson, Parker, Wise and Montague counties had received the most damage.
The newspaper said power outages had darkened thousands of homes in the Grand Prairie area and elsewhere in the region.
A tornado was on the ground near Granbury and the nearby Rancho Brazos subdivision was evacuated after about 40 homes were damaged. There were reports of people injured and a possible gas leak.
The tornado in Millsap captured by Storm Chase Media.
There are multiple fatalities, reports CNN.
Kathy Jividen, a spokeswoman for the Hood County, Texas, sheriff's office said there were "multiple fatalities" in the wake of the storm.
Hood County Judge Darrell Cockerham said there were reports of homes being flattened with people inside.