Say "bank run" and many people conjure black-and-white photos from the 1930s — throngs of angry depositors clamoring for their money. But the sudden collapse of Silicon Valley Bank and Signature Bank shows how in an age of instant communication and social media, a financial panic can go into hyperdrive, facilitated by the ability to make instantaneous bank transfers and withdrawals.

How fast did it happen? Consider that when Washington Mutual experienced a run as it collapsed in September 2008, depositors withdrew $16.7 billion over a 10-day period. By contrast, customers at Silicon Valley Bank tried to withdraw $42 billion — more than twice as much — in a single day, last Thursday.

"You have transactions that can be done much faster ... and get cleared much faster," says Reena Aggarwal, the director of the Psaros Center for Financial Markets and Policy at Georgetown University.

"So, everything speeds up," she says. "I think that's partly what happened here. But at the end of the day, it's the underlying problems at the bank that caused this."

"All of that obviously makes this happen very quickly," Aggarwal says.

Mohamed El-Erian, an author and chief economic advisor at the financial services giant Allianz, tweeted that "supersonic speed of information flows" in an era of "tech-enabling banking" contributed to the rapidity of developments. Meanwhile, OpenAI CEO Sam Altman, referring to the bank collapses that preceded the Great Recession, tweeted on Sunday that "The world has changed since 2008; the speed of a cascade could be very fast."

Regulators stepped in on Friday to close Silicon Valley Bank after it was forced to take a $1.8 billion hit when it dumped some long-term U.S. treasuries. The news spread quickly, sending jittery depositors — among them companies such Roku and a slew of high-value startups — scrambling to withdraw cash and causing the bank to go under. New York's Signature Bank, heavily exposed to cryptocurrencies and the tech sector, followed suit in short order over the weekend. Silicon Valley and Signature are the second- and third-largest bank failures, respectively, in U.S. history.

On Sunday, the federal government launched an emergency program to curb any possible contagion from the bank failures. In a joint statement, Treasury Secretary Janet Yellen, Federal Reserve Board Chair Jerome Powell and Federal Deposit Insurance Corp. Chair Martin Gruenberg pledged that Silicon Valley Bank and Signature Bank depositors would have access to all their money. A third financial institution, First Republic Bank, is teetering amid concerns about its high reliance on unsecured deposits from wealthy customers and businesses.

Jonas Goltermann, a senior economist at Capital Economics in London, agrees that social media has helped drive the bank runs in recent days. Social media has become interwoven into our social and financial lives, he says.

"That wasn't the case even 15 years ago," Goltermann says, referring to the 2008 financial meltdown.

But there's a possible upside to the lightening-fast transfer of financial information, according to Georgetown's Aggarwal.

"In terms of a run, you have to get from one equilibrium point to another equilibrium point," she says. In other words, the system needs to find its balance.

During the Great Depression, for example, coming to grips with the economic situation took a lot of time because the flow of information was slower.

Today, that process is sped up. "I think it's better to come to that new equilibrium sooner rather than bleed through it over days and weeks and months," Aggarwal says.