Changes In Climate Threatens Snowpack And Livelihoods

Apr 5, 2021

It's no secret that Wyoming produces a lot of beef. After all, agriculture is Wyoming's third-largest industry. But producing anything in this state requires a lot of resources, especially water.

"Water is the lifeblood of the West. And that's overused. But yet it's entirely true," said Shanon Sims.

Sims is a rancher in McFadden - a tiny town in southeast Wyoming. His family has been raising cattle for four generations at Sims Cattle Company, and they're teaching the fifth.

"I'm only 40 years old and so I've not seen any huge drastic changes that you wouldn't kind of suspect anyway," said Sims. "But that being said, when I first started irrigating and whatnot in the mid-2000s, it was fairly simple."

Precipitation was more consistent with snowmelt that lasted throughout the spring, which made it easier to plan their irrigation. That matters because they have a pretty sizable ranch - 900 head of cattle move between irrigated upper pastures and floodplain lower pastures. They also produce a small amount of native hay in irrigated pastures to help sustain them for a few winter months. Building a reservoir of their own is expensive and the ranch doesn't have a good location to put it. So changes in precipitation are a big deal on the ranch.

"Over the last three or four years, our rainfall has gotten really sporadic, we'll get huge amounts of precip in the spring, and then it won't rain all summer," said Sims. "Or it'll happen just the opposite and we won't get that spring precip. And so the irrigating gets more complicated."

Sims is noticing something that researchers have been warning against for years. A warming planet can cause normal precipitation patterns to fall out of whack. It can lead to droughts, especially in areas already prone to them like Wyoming.

According to the National Resource Conservation Service here in Wyoming, the state's precipitation this water year (October 1, 2020 till September 30, 2021) has been lower than usual. But a few weeks ago, a winter storm dumped huge amounts of snow on the area, bringing levels just over normal in most places.

"This year was looking like it was going to be a terrible drought, and for most of the West, I think it still is. We're sitting at 110% of normal snowpack. And so we're looking really good right now," said Sims. "But if it doesn't snow between now and the first of May, then we're behind again. It just changes that fast. We're always two weeks away from drought."

Winter snowstorms create drifts that slowly water the pasture as they melt.
Credit Sims Cattle Company

Snowpack. It's especially important in the west. That stored moisture helps create a steady freshwater supply as it melts throughout the spring. It fills the rivers and reservoirs where we get our drinking water and the irrigation ditches of ranchers like Sims.

But warming temperatures threaten how long the snowpack lasts.

"We can actually identify for every one degree [Celsius] increase, we have 4.75 days early onset of spring snowmelt," said Dr. Jacqueline Shinker, a University of Wyoming professor who studies climate change and water resources in the Intermountain West.

According to Shinker, as temperatures rise, the snow starts to melt earlier than average. Shorter-lived snowpack means less stored water available to be shared.

"An understanding that increases in temperature lead to early snowmelt and lead to increases in evaporation and diminished late-season flows in our streams, of which we have headwaters to three of the major rivers in the United States, is a pretty powerful thing," said Shinker.

For example, in 2012, parts of the Platte River went dry because of the extreme drought, threatening the drinking water of many Nebraskans.

Turns out new research from the Scripps Institution of Oceanography shows that snowpack in the Rocky Mountain Region will be less affected by warming temperatures than other areas. That's because one degree of warming is small relative to the large temperature swings our area normally experiences between seasons. This means snow should only melt a few days earlier than usual - not as drastic of a change compared to regions with less seasonal temperature change, like the coast, which could see melt almost a month earlier.

But that's if you have snow to melt. According to Shinker, warmer springs may mean historically wet spring snow instead falls as rain, which is nearly impossible to store. Not only that, but rain that falls on existing snowpack degrades it and helps it melt faster.

So, as western snow continues to face threats, municipalities, ranchers, and other agencies will have to change their management strategies. Without proper water resources here in the state, Wyoming beef wouldn't be able to feed people around the world like it does today, and ranchers like Sims and his family could lose their way of life.

"It's up to us as managers to adapt to whatever's coming our way. We can't control the weather, we can't control regulations, and so it's up to us to adapt and I think just embracing what we've got in front of us right here right now is probably the most important thing we can do," said Sims.