As millions of Americans head online or to stores to shop for the holiday season, they may experience a shortage of items and longer delivery times. 

Since the pandemic has started, the United States has seen a variety of supply chain issues that have caused shortages in products, inflation and other problems for both consumers and suppliers. 

U.S. Secretary of Transportation Pete Buttigieg told Yahoo Finance Live that supply chain issues will remain as long as the world remains in a pandemic. 

“I think that a lot of the issues at the beginning of the pandemic were due to consumer behavior, purchasing more of certain products,” Jennifer Ryan, the chair of the University of Nebraska-Lincoln’s department of supply chain management and analytics, said. 

Those issues experienced at the beginning of the pandemic are still partly to blame for the current issue, but new problems, such as an imbalance between demand and supply, are much different. 

Prior to the pandemic, the supply chain was working well, according to Ryan. If someone wanted to purchase something online, they could get it in a couple of days. Everything was working in balance to ensure that the supply was meeting the demand, she said. 

Now the issues come down to supply and demand. The pandemic has hit various parts of the world at different times which have led to shortages in some supplies, Ryan said, like semiconductors, which are crucial for cars and video game systems. Without these pieces, it is hard for consumers to purchase products like the PlayStation 5.

One of the notable problems that has been seen in recent months is the backing up of container ships in the ocean, Ryan said. Ships sit off the coasts of California for months at a time waiting to unload their cargo in the ports. This has caused issues in supply, Ryan said. It can also lead to companies paying more to fly supplies to them, but when the ship is finally unloaded, they have double the amount of goods. 

“It’s causing distortions in the supply chain,” she said.

With Black Friday and Cyber Monday just a week or two away, Ryan encourages consumers to buy early.

“I think you wouldn't want to wait until Cyber Monday,” she said. “I would say, the only way to get ahead of it, if you're going to do online shopping, is to order now. Order early.”

Heng Chen, an assistant professor of supply chain management and analytics, said consumers can expect to see higher prices, shortages in products and limited selections around the holidays. 

“Clearly there will be delays and decreased inventories and less deals,” he said. 

In her 25 years studying and researching the field, Ryan said she’s “never seen anything like it.” 

To fix these issues, companies need stability, according to Ryan. 

“They need the pandemic to end,” she said. “They need the world to settle into whatever the new normal is going to be and then things can start to resolve themselves.”