Massive fire breaks out in San Antonio, Texas

Shafaq News/ A massive fire broke out in San Antonio, Texas.

The blaze began at an apartment complex in Bexar County.

Residents said they received an alert to turn off their water heater, and the fire erupted on the second floor moments later.

About 50 residents were evacuated from the building.

Firefighters had to usher in water to extinguish the flames because a nearby fire hydrant was frozen.

Videos and photos on social media shows black smoke billowing into the sky as fire crews work the scene.

No injuries have been reported. Officials continue to investigate what caused the blaze.

Earlier this week a deep freeze in the Lone Star state, which relies on electricity to heat many homes, is causing power demand to skyrocket. At the same time, natural gas, coal, wind and nuclear facilities in Texas have been knocked offline by the unthinkably low temperatures.

That nightmarish supply-demand situation has sent electricity prices in energy-rich Texas to skyrocket more than 10,000% compared with before the unprecedented temperatures hit. Texas has been hit with life-threatening blackouts. More than 4 million people in the state were without power early Tuesday.

In response, Governor Greg Abbott has called for an investigation into the nonprofit Electric Reliability Council of Texas, known as ERCOT, which controls most of the state's grid. The group's CEO on Tuesday defended the controlled outages, saying they "kept the grid from collapsing" and sending the state into a complete blackout.