https://www.cnet.com/news/hurricane-harvey-phone-service/

Cellular service held up better during Harvey than in past storms, which is surprising given the scope and size of the disaster. Harvey devastated hundreds of miles of coastline from Corpus Christi, Texas, to Lake Charles, Louisiana. The flooding covers an area that's roughly the size of Lake Michigan and is home to more than 4.5 million people. A week after the storm first made landfall in Texas, waters are receding, but some roads are still impassable.  

Not every area's cell coverage fared well. In the four counties along the Texas Gulf Coast where the hurricane first made landfall, there were significant outages, leaving tens of thousands of people without phone service. Last weekend in the immediate aftermath of the hurricane, Arsanas County in Texas reported nearly 95 percent of its cell towers were out of commission, according to the Federal Communications Commission.