What's the best signal that fall is arriving? A cooling of temperatures and changing of the leaves? Football on Saturdays and Sundays? Or is it the grocery store beer cases being stocked with pumpkin-flavored brews? The latter autumn tradition may be in danger due to a shortage of the gourds, reports Draft.

Fortunately for those who love the sweet and spicy flavors of fall seasonals, it looks like the shortage hasn't reached critical levels — at least not this year. But, it is making life tougher for brewers who produce variations of the style. Paul Kavulak, co-founder of Nebraska Brewing Co., told Draft "a few years were dropped from my lifespan" in the process of finding enough pumpkin puree for Wick For Brains, the brewery's annual fall release.

"We bought enough for maybe the first two batches and then went back to buy more — being good disciples of Just in Time Inventory — and were told they were out," Kavulak said. "We had to brew [Wick For Brains] five times this year, so you can see the panic that set in. My guess is that this is going to be an issue across the board."

The lack of pumpkin available for beer in 2016 stems from a significant crop shortage in 2015. Last year's harvest was down about 50 percent from normal levels, according to CNN. Market experts were expecting a shortfall of canned pumpkin puree to hit around the time Americans were planning to make their Thanksgiving pies, but that didn't happen. Fortune reports the 2015 holiday was saved by producers burning through their reserve stock, thus kicking the can down the road. Now, it appears the cupboard is pretty bare. Brian Nelson, head brewer at Hardywood Park in Virginia, told Draft supply may be tight for brewers and bakers alike.

"I was able to patch it together this year and I referred this supplier to a couple other Virginia breweries that I'm friends with," Nelson said. "We'll be fine this year, but I know there are other small breweries scrambling. And I hear it's not only in the brewing industry but in the culinary industry as well."

However, consumers who crave Starbucks's Pumpkin Spice Latte and the many other "pumpkin spice" flavored comestibles needn't worry. Most of those products contain no pumpkin at all.

• Brewers struggle to find pumpkin for this year's fall brews [Draft]

• The great pumpkin shortage of 2015 [CNN]

• Here's What Happened to the Great Thanksgiving Pumpkin Shortage of 2015 [Fortune]

• 49 Pumpkin Spice Foods That Have No Business Being Pumpkin Spiced [E]