In the fog of disaster, hundreds of thousands of people worldwide tried calling their loved ones in the Boston area. The Boston metropolitan area’s robust mobile networks simply clogged up as Verizon, AT&T, Sprint, T-Mobile, and other providers coped with a massive and unexpected surge. In the aftermath of natural disasters, terrorist attacks, and anomalous incidents worldwide, telecommunications networks simply can’t cope with the sharp increase in call volume. Can that be fixed?

On Monday, mobile providers scrambled to cope with the unexpected call volume increase and to urge users not to make voice calls. For example, Verizon issued a terse statement saying they were “enhancing network voice capacity to enable additional calling in the Copley Square area of Boston. Customers are advised to use text or email to free up voice capacity for public safety officials at the scene.”

In an email to Fast Company, Thomas Pica, Verizon’s executive director of corporate communications, said that although Verizon “has a significant amount of margin in (their) system,” significant events could exceed local capacity at individual cells. In addition, when sudden disasters such as the Boston attack do happen, engineers at mobile providers can monitor and adjust network elements in real time.

Users of every major mobile carrier reported outages in the Boston metropolitan area. This lead to the spreading of unconfirmed rumors which were taken as facts by the media, such as the Associated Press incorrectly reporting that mobile service had been shut off in Boston to prevent remote detonation of bombs with mobile phone times. A law enforcement official told the AP that a shutdown was taking place.

Mobile networks, whether 3G or 4G LTE, have bandwidth that is more than sufficient 99% of the time.

What did happen in Boston, however, was a routine swamping of mobile networks that takes place whenever an anomaly incident occurs. Shortly after hurricane Sandy, (now former) FCC chairman Julius Genachowski warned that mobile service was devastated by the storm. Although Sandy involved a physical destruction of mobile network infrastructure that was very different from the simple heightened call volume of Boston or the 2007 San Francisco earthquake, the basic elements are the same.

Mobile networks have bandwidth that is more than sufficient 99% of the time. However, when disaster strikes, the decentralized nature of the network means that whole geographic regions can be knocked out by increased call volume. Whenever the generous-but-finite bandwidth at carrier site buildings are strained, users are prevented from making voice calls. Because SMS text messages take up far less bandwidth, mobile carriers instead encourage users to text message each other. As Pica put it to Fast Company, “text requires less dedicated real-time capacity than voice. Data networks including LTE and EVDO were not impacted due to the nature of the way data systems are used.”