Jamie Barnett was quoted by WIRED on August 29, 2017, in an article discussing system improvements during hurricane Harvey. The Texas 9-1-1 system has been heavily burdened with calls, but "those calls are going through" Barnett says. "By and large we're hearing that the cellular networks stood up. That means there's been some learning."
Some areas of southeast Texas completely lost connectivity, but the Federal Communications Commission says "just 4 percent of the 7,804 cell sites in Harvey's path were wiped out." This is in comparison to the more than 1,000 cell sites that were knocked out during Katrina.