Shoppers gazed high and low as they rolled their carts down the paper-goods aisle at Costco in St. Louis Park on Monday. The bathroom-tissue and paper-towel shelves were completely cleared, causing shoppers to ask if paper products had moved to another aisle.

Consumers around the Twin Cities and nationwide flocked to stores over the weekend and on Monday to stock up on hand sanitizer, cold medicine, toilet paper and other supplies amid concerns about the coronavirus outbreak. Empty shelves of certain products could be found around the metro.

An employee told shoppers that the Costco store had run out of toilet paper and would be restocked later in the week.

Amid the shopping frenzy, a number of retail stocks surged on Monday. Costco’s shares rose 10%, Walmart’s increased 8% and Minneapolis-based Target’s stock was up nearly 6% on a day when the market also rose more broadly.

There have been no confirmed cases of coronavirus in Minnesota. But last week, state officials encouraged Minnesotans to begin preparing for the possibility of it spreading here by stocking up on supplies as well as washing their hands and covering their coughs.

Over the weekend, social media was flooded with pictures of empty store shelves around the Twin Cities and in many other parts of the U.S.

On a spot check Monday afternoon, the shelves for hand sanitizer as well as medical masks and gloves were empty at the downtown Target on Nicollet Mall.

The Target in Burnsville also was at least temporarily out of hand sanitizer Monday morning.

The Menards in Bloomington was out of masks as well.

Some Lunds & Byerlys stores in the Twin Cities “have limited or no inventory of hand sanitizer at this time,” according to spokesman Aaron Sorenson.

“We have also seen an increase in sales with regard to disinfecting wipes, cleaners, canned goods, bottled water, soup and bath and facial tissue, but our inventory levels are still in good shape on those items.”

Hy-Vee officials reported spikes in sales of hand sanitizer, but it remained in stock in Twin Cities’ stores with more shipments on the way.

A Target spokeswoman said the company would address the effect of the coronavirus on its business at its investors’ meeting Tuesday.

That meeting was originally scheduled to be held in New York, but the company hustled over the weekend to change course given the “rapidly evolving situation” with coronavirus and will instead broadcast it remotely from its headquarters in Minneapolis.

Checkout lines at the St. Louis Park Costco stretched into nearby aisles on Monday afternoon with eight to 10 carts behind each register.

“I can’t remember seeing checkout lines so long on a weekday,” said one employee. “But they were even longer over the weekend.”

The research tracking firm Nielsen said it has found significant spikes of stockpiling of emergency supplies in the U.S., China and Italy. It said consumers are rushing to build “pandemic pantries.”

In the U.S., sales of medical mask rose 378% in the four weeks ended Feb. 22. Hand-sanitizer sales were up 73% in that same time frame, according to Nielsen.

Consumers also are stocking up on canned goods, flour, sugar and bottled water, the firm said.

In the U.S., sales of supplements, fruit snacks and first-aid kits have also been rising.

Nielsen said it also expects online shopping to spike in the U.S. as people become increasingly interested in reducing exposure to others.