People Are Panic Buying for the Winter Storm. An Expert Explains Why We Do It

As a potentially historic winter storm has already knocked out power to 112,000 homes and warnings are in place for some 140 million Americans, many in the storm’s path have rushed to stores to stock up on supplies.

Images of shelves stripped bare at stores across the country have found their way to social media as the storm started to sweep its way east from Texas on Saturday morning, with freezing rain and snow reports in Kansas, Oklahoma and Arkansas.

Read More: How to Prepare for a Winter Storm Power Outage

Images of Trader Joe’s stores in Washington, D.C., and Chelsea, New York City, show empty aisles. Meanwhile, further south, grocery stores in Charlotte, North Carolina, saw an influx of customers stocking up on water, non-perishable food items and canned goods, as well as batteries. Locals in the area reported that water was sold out at their Harris Teeter.

But are people right to stock up, or is this another case of unwarranted panic buying? And what is the difference between being prepared and being paranoid?

Hersh Shefrin, professor of behavioral finance at Santa Clara University, says that this phenomenon is not uncommon in the face of a major weather event or high-stress situation.

“It is certainly reasonable to stock up for a few days,” he says, but once the buying is driven by a “fight or flight” emotional response, that’s when it transforms into panic buying.

“There’s a difference between emergency preparedness and panic buying,” Shefrin tells TIME. “So I think that what we would like in an ideal world is that when there’s an impending storm, that people engage in reasonable, sensible emergency preparedness, but when fear takes over, then people become focused on worst-case scenarios.”

Panic buying can be heavily influenced by other people, he says. 

“When people start to panic buy, their impulses take over,” he continues. “So, if they’re in a shop and they see that there’s some item that wasn’t on their shopping list, but they just see that the stock of a certain item is going low, they [might] think, ‘Oh, I better get that before they’re all gone.’”

Shefrin says the best way to prevent actual shortages is for consumers to stop and not let their emotions take over.

Behavioral scientist Ravi Dhar, a professor at Yale University, says that the “inherent uncertainty” of the storm’s severity this weekend leads people to try to control what they can.

“People tend to be overly risk-averse and have a desire for control rather than hysteria,” Dhar tells TIME. He says that the “risk of running out feels worse than overspending,” as people can rationalize to themselves that they need the goods later. 

“The salience in the media…and constant weather alerts on apps makes the event seem more scary psychologically,” he adds, arguing that people then react to emotions instead of the probabilities of harm, especially as the media continues to use words including “historic” to describe the storm.