State is also experiencing rolling power blackouts as temperatures drop into the single digits.
T-Mobile customers in Texas were hit by a service outage on Monday as a powerful winter storm paralyzed much of the state.
Angry customers complained on DownDetector of being unable to make calls or text since about 6 a.m. PT on Monday. The outage appears to be affecting customers in major cities from north to south, including Dallas, Houston and Austin.
"We're experiencing network issues following severe weather in several areas of the country and especially across Texas," Neville Ray, T-Mobile's president of technology, wrote in tweet. "Our teams are working hard to restore service."
The operator of Texas' electrical grid said early Monday it's instituting rolling blackouts across most of the state amid a massive winter storm that's shut down much of the state. The temperatures for Dallas and Austin were in the single digits Monday morning, and many roads were iced over.
President Joe Biden declared a federal emergency across the state.