Ten years ago, the average price of a 16-ounce chip bag was less than $4.50. These days, it’s around $6.50.

While many products saw huge price increases early in the pandemic and after the public health emergency ended, the rising price for a bag of chips has outpaced inflation for other grocery items. There are various reasons, including transportation costs, which increase when local crops near potato chips factories wither in the heat.

On a recent day, Kevin Troyer watched a truck unload his August potato crop in Waterford, Pennsylvania.

“These loads are coming in fresh out of the field,” he said.

The haul of white-skinned, starchy potatoes tumbled out of the truck to his conveyor system, where they were washed and sorted.

The crop looked pretty healthy — good news, because farming potatoes is becoming more challenging in Pennsylvania

Unlike potato growers in the southeastern part of the state, Troyer’s farm has been lucky with the weather this season; potatoes need cool nights.

“Last night, it was down … I think I had 49 [degrees] at my house. And actually, potatoes love that kind of weather,” Troyer said.

The cleaned potatoes were loaded onto another truck headed to a Snyder of Berlin potato chip factory a few hours south, near Pittsburgh. They were to be made into chips within 48 hours.

“The big season for potato chips is right around the holidays and the football playoff. Everybody’s having their Super Bowl parties,” he said.

Pennsylvania has more potato chip makers than any other state, and factories like to source from nearby because it reduces the need for long-distance transport. Fuel costs are a major factor in the rising price of potato chips.

But growing potatoes in Pennsylvania is becoming more difficult because of climate change.

Potatoes are tricky to grow, especially in the heat

“The crop is sensitive to weather conditions,” said Bob Leiby, an agronomist with the Pennsylvania Co-Operative Potato Growers.

Weather conditions like temperature. According to the Pennsylvania state climatologist, in the 1980s in Erie, around Kevin Troyer’s farm, there used to be 35 nights a year when temperatures were too hot for potato growth. Today, it’s more like 50 nights a year.

And hotter days are also hard on the crop.

“It’s easy to get soil temperatures way up out of the range that tubers will even continue to grow,” Leiby said.

If the soils hit 85 degrees for long enough, the potato crop is fried.

A push to maintain Northeastern U.S. potato crops

“The climate is changing, and changing kind of rapidly, and we have to develop potatoes that are adapted to the new climate,” said Walter De Jong, who researches potato genetics at Cornell University.

The biggest U.S. potato-growing states, like Idaho and Washington, have the advantage of larger tracts of land, a longer growing season and large-scale mechanized irrigation systems. However, sourcing potatoes from further away means higher transportation costs for Pennsylvania chip factories, and De Jong thinks it’s less sustainable.

“Do they have the water to sustainably use to grow all those potatoes indefinitely out West? I think the answer to that is no,” he said.

In 2011, Cornell released a potato De Jong developed that helped Northeastern U.S. farmers store their crop long enough for the football season chip rush, which means fewer potatoes from out of state.

Transportation costs are just one aspect of potato chip prices, but after the food shortages and supply chain snags of the COVID-19 pandemic, De Jong thinks there are reasons to keep potato production close to the factories.

“In general, potatoes produced out West may be cheaper, but there is some societal value for those disaster years to have production in the Northeast as well,” he said.

Because local potato production could mean cheaper chips, just in time for football season.