As wildfires raged across California, mobile phones went silent as towers and lines succumbed to the flames.

“We had to drive through neighborhoods with sirens and public address systems to alert residents and visitors,” said David Katz, a spokesman for the Malibu Search and Rescue Team. “In some cases, we had to go house to house on foot.”

Those experiences during the widespread fires that claimed more than 70 lives — as well as during and after hurricanes earlier this year — reveal a downside to the wireless communications upon which Americans are increasingly dependent: Mobile service falls short of old-fashioned landlines when it comes to surviving catastrophic events.

That can leave citizens unable to receive automated warnings or call 911 for help.

“The current technology gives us ubiquity, but not great resiliency,” said Jamie Barnett, a partner at the Venable law firm and former chief of the Federal Communications Commission’s public safety bureau.

More than half of U.S. households — and more than 70 percent of adults renting their homes — rely on mobile phones, according to survey results from the U.S. Centers for Disease Control.