Warmer temperatures descend on the Klamath Basin

Words by Alex Schwartz, Photos by Arden Barnes

Herald and News / Report for America

Wizard Island sits in the caldera of Crater  Lake on Oct. 16, 2021.

Mazama’s gone! but in his wake,

A lovely jewelled sapphire lake,

Born of chaos, fire and smoke,

Turbulent nature didst invoke

Mazama’s fall — that thou shouldst be —

Silent, mysterious sapphire sea.

—Belle Meyer

Giiwas has endured continuous change. It began its life as a massive mountain frosted with glaciers, until a volcanic battle turned it into a barren chasm.

Now it sports a mosaic of ancient conifers, open meadows and kaleidoscopic cliffs cradling a vast cobalt lake — Crater Lake, as most call it today.

Standing on the rim of the caldera, it’s hard not to think about the millions of years of geologic luck that led to this place.

Tectonic plates beneath North America and the Pacific Ocean collided at just the right angle to force magma through the Earth’s crust, providing the molten fuel to create a vast volcanic plateau. Gently sloping shield volcanoes formed on top of it, followed by the snow capped cones of the High Cascades a few hundred thousand years ago. Glaciers, some a thousand feet thick, carved deep canyons into the mountain’s slopes as recently as 10,000 years ago.

Fire took over again roughly 7,700 years ago, when a cataclysmic eruption (or, as the Klamath story says, a battle between two powerful spirits) collapsed Mt. Mazama’s summit, spewing gas, pumice and ash hundreds of miles and obliterating the lush forests that surrounded the mountain.

Water allowed life to return to the hollowed volcano. No longer a mountain, Mt. Mazama became a 7,000-foot rain bucket, trapping precipitation blown in from the Pacific Ocean. Storms brought rain and snow to the nutrient rich volcanic soils. Over thousands of years, the caldera filled with water and became a tranquil, sapphire pool fringed by verdant trees. Various Indigenous groups in the area who had witnessed the eruption, including the Klamath and Modoc, began to consider the lake a deeply spiritual place.

The “Phantom Ship” at Crater Lake on Oct. 5, 2021.

The “Phantom Ship” at Crater Lake on Oct. 5, 2021.

In 1902, the land became one of the United States’ first national parks, largely shielding it from development.

But Crater Lake National Park, as beautiful and protected as it is today, is not immune to a warming atmosphere. Neither is the 16,000-square-mile Klamath Basin, upon which the flooded caldera sits like a crown jewel.

The weather station at the park’s headquarters has shown a rise in average temperature of about 1˚F since the mid-20th Century. That may not seem like much, but it’s already having a measurable effect on the park’s ecosystems.

The lake itself, despite its impressive clarity, size and depth, is changing.

According to the park’s 2020 “State of the Lake” report, the period of warm water temperatures in summer has lengthened by 33 days since 1965. That has caused the average summer temperature of the lake’s surface to increase by 5.6˚F. 

Warmer waters allow more invasive crayfish — introduced to the lake in 1915 as food for stocked fish — to survive and spread throughout the lake’s shoreline, encroaching on habitat of the endemic Mazama newt. And never-before-seen algae blooms in the impossibly clear, cold lake have formed during the past decade, potentially linked to warmer water and the crayfish boom, among other factors.

The park’s idyllic mountain summers, when the sky and the lake seem to compete over who can be the most blue, are becoming clouded with smoke from the region’s ever-intensifying wildfires. Some days, the air becomes so thick with particulates that park staff and unlucky visitors get a feel for what it must have been like during Mt. Mazama’s eruption, when ash darkened the sky.

John Duwe, the education coordinator for Crater Lake National Park, on Oct. 5, 2021

John Duwe, the park’s education coordinator, said the park itself hasn’t been spared from the blazes, either. In 2017, ten fires in the park burned more than 20,000 acres, or about 10 percent of the park.

“We’re seeing massive acreage in Crater Lake that’s burned, and it’s all been burned in the last 15 years,” he said. “We’re at some sort of tipping point.”

Fire has always been part of the landscape around Crater Lake and in the Klamath Basin at large, but weeks of poor air quality and low visibility due to smoke are a new horror, chalked up to explosive megafires caused by a perfect storm of decades of fire suppression and climate-driven shifts in fire weather. Beyond making it difficult to do monitoring and maintenance in the park, the airborne ash simply prevents people from enjoying the outdoors. Duwe, who lives near the southern boundary of the park in Fort Klamath, has seen that firsthand.

“I moved to the basin for recreation, especially summertime hikes and bike rides,” he said. “Now, I need to take advantage of the shoulder seasons and prepare to be hunkered down for July and August.”

Perhaps most concerningly, Crater Lake is losing its snow. On average, 34% less snow falls in the park today than it did in the 1930s, equating to a loss of about 1.6 inches of snow-water equivalent per decade.

Thanks to the park’s position near the headwaters of Upper Klamath Lake, the behavior of snow here is a bellwether for how much water will enter the lake each summer. If the snowpack is thick and dense enough come spring, and if temperatures warm gradually into early summer, it forms a natural reservoir.

Snowmelt-fed tributaries flow down from the park in the spring, filling Upper Klamath Lake just in time for suckers to begin spawning, farmers to begin diverting irrigation water and flows to increase on the Klamath River. Under ideal conditions, enough snow remains at high altitudes to keep things flowing during the dry season, even without significant summer precipitation.

If the snowpack doesn’t accumulate enough or melts off early, streamflows peak earlier in the spring. That leaves more liquid water— instead of snow— in the system to evaporate during the summer. The natural reservoir runs out right as it’s most needed, sending the basin below into chaos. That’s what has been playing out recently in the Klamath Basin — a scenario that could become even more common as the climate warms.

But the decline in Crater Lake’s snowpack isn’t unique. Warmer temperatures across Oregon have pushed freezing air into higher altitudes, causing winter storms to drop a greater portion of their moisture onto the Cascades as rain rather than snow. Warmer springs have also caused snow to melt earlier and more quickly than it used to. 

Due to warmer atmospheric temperatures, snow droughts — when a greater-than-normal percentage of precipitation falls as rain in a snowmelt-dominated system — are expected to increase sharply in both frequency and intensity by the middle and end of this century. This happened in Water Year 2015, when despite receiving a normal amount of total precipitation, the basin’s peak snow-water equivalent was one of the lowest on record.

Between 1982 and 2017, all mountains in Oregon accumulated snow more slowly, grew thinner snowpacks and melted out earlier than average, according to Oregon’s fifth Climate Assessment published in 2021. In some areas of the southern Cascades, peak snow-water equivalent (the maximum amount of water stored in the snowpack each year) has declined by as much as 3.5 inches per decade since the early 1980s. This year, the Klamath Basin’s snowpack melted out nearly a month earlier than normal.

The sun sets behind a snow covered peak at Crater Lake National Park on Oct. 16, 2021.

The sun sets behind a snow covered peak at Crater Lake National Park on Oct. 16, 2021.

John Duwe stands next to a Mountain Hemlock covered in lichen on Oct. 5, 2021. The line where the lichen stops growing is typically the height of the average snowpack at Crater Lake.

John Duwe stands next to a Mountain Hemlock covered in lichens on Oct. 5, 2021. The line where the lichens stops growing is typically the height of the average snowpack at Crater Lake.

Reduced snowpack has other impacts, too. Instead of spring melt that slowly percolates into the soil, winter rain leads to faster runoff and erosion. Trees may enjoy the abundant water in early spring, but drier soils in late summer can leave them stressed and prone to disease. Though the long-term trend in precipitation has remained relatively steady at Crater Lake and throughout much of the Klamath Basin, a wet winter no longer translates to a wet year.

“Even though we seem to be getting the same amount of precipitation, if we don’t get snow it doesn’t really do us much good,” Duwe said.

What is drought?

Most natural disasters are pretty easy to see.

You can watch a hurricane form and intensify before it makes landfall, dissipating after being cut off from the warm waters that fueled it. Thermometers rise during heat waves, waters rise during floods and seismometer pens wiggle with the rumbling of fault lines.

Droughts are different — they’re insidious. They fade into and out of existence slowly, often materializing when we’re not looking. They don’t appear readily in satellite imagery, and they don’t blow in all at once. Whereas powerful storms and raging infernos are clearly singular events, droughts occupy a negative space: A discrepancy between the amount of water a system needs and how much is available. As it turns out, it’s a lot harder to keep tabs on the absence of something good than the presence of something bad.

Four Types of Drought


The most short-term of droughts, resulting from below-average precipitation and above average evaporation. If temperatures mellow out and precipitation increases relatively quickly, effects can be minimized.

Tule Lake Sump A sits mostly dry from where the water has been drained to Sump B to try and prevent the spread of Avian Botulism. Eventually, Sump A will be refilled to create a food supply and better environment for the waterfowl in the area. June 8, 2021.


Over time, meteorological drought can dry out soils and hinder groundwater recharge, reducing the amount of water available to enter streams, lakes and aquifers. This can occur over multiple years with low precipitation or high temperatures, and it doesn’t end with a single storm.

The Bootleg Fire will have major negative impacts on the Klamath watershed.  Sept. 13, 2021.



Hydrological drought begins to dry out crops, forests and grasslands. Vegetation stress increases, along with wildland fire risk.

Mouth of the Klamath


Supply from an area’s water sources cannot meet the demands of its users and environment. Can affect the supply of commodities and political stability in a region and are caused by a combination of physical factors and human systems.

When winter sets in on the Klamath Basin — after crops have been harvested, hunting and fishing trips have concluded and the heat of summer has dissipated — people do their best to will the storms to come. Those concerned with water availability in the basin religiously watch precipitation totals during the wet season, hoping the bell curve of accumulated snow will reach or exceed the average by spring like an exhausted marathon runner crossing a finish line. 

But precipitation is just one indicator climatologists use to evaluate a lack of water. In fact, there hasn’t been much change in annual precipitation in the Klamath Basin over the past 90 years. What happens to water after it arrives is just as important.

Larry O’Neill, Oregon’s state climatologist, said temperature is a big driver of how much precipitation actually becomes available to waterways and water users during a given year. One of the most basic tenets of climate change is that a warmer atmosphere can hold more water. While that leads to more powerful storms during wet periods, it also means more evaporation during dry periods.

This intensification of the water cycle is altering the very hydrology of watersheds.

“The atmosphere will become thirstier, in a sense. And it will pull more moisture out of the landscape quicker,” O’Neill said. “You’re going to be starting off with a groundwater deficit.”

Hotter summers are leaving soils, aquifers and vegetation more parched, causing more runoff to be absorbed into the land when precipitation does arrive. And with warmer winter temperatures, the snowpack is holding less water to make up for increased dryness. Such conditions turn meteorological droughts into hydrological ones more regularly, leading to long-term water deficits.

“Having your wet season be wet is not enough to necessarily say that drought is not present or it’s over,” O’Neill said.

In February 2021, the U.S. Drought Monitor had already classified much of the Klamath Basin under “extreme” drought, even though more than 60 inches of snow blanketed the slopes of Crater Lake. It’s difficult to imagine the basin plunged into drought in the middle of winter, when nobody’s fighting over water. But in reality, 2021’s drought began nearly two years ago.

Maps from the U.S. Drought Monitor

November 19, 2019, was the last time the Klamath Basin sat colorless on the drought monitor map. But a dry winter began to change that — a measurable snowpack didn’t arrive until the end of the month, plateauing mid-winter at a little more than half of average. By late March 2020, drought had returned to the entire basin — with much of the Oregon portion of the watershed in “severe” drought. 

Four months later, at the height of a particularly hot and dry summer, a thick, red band of “extreme” drought ballooned across the basin. Such rapid intensification of drought conditions is referred to as a “flash drought.”

Things only worsened last fall, which brought little alleviating rain. Soils and vegetation thirsted for moisture, creating a deficit that would eat away at the upcoming winter’s snowpack. The red band tightened its grip — then the maroon appeared.

“Exceptional” drought had only been designated one other time in Oregon since the drought monitor began 21 years ago: the summer and fall of 2003 in Malheur County. But historic conditions this summer meant it was time for a comeback.

O’Neill heads a committee that advises the national drought monitor on how they should draw their map in Oregon. They used a variety of indicators, including precipitation, soil moisture, streamflows and evaporation to add a dark blob at the center of the state in April 2021.

The Story Behind the Drought

Drought or aridification?

The West’s current megadrought has been one of the region’s driest periods on record. Though wetter precipitation patterns will likely return someday, climatologists say the flashier hydrology now dominating the region could sharpen the sting of summer drought regardless of what happens in wet seasons. 

Hydrographs are already showing this change — the annual flow of the Williamson River has experienced a lower peak and a deeper trough over the last three decades than throughout much of its period of record.

Though temperature-driven changes to water on landscapes are more straightforward, scientists are still evaluating whether climate change is altering the way storms behave on those landscapes. Thanks to its location — in a transition zone between the more temperate Pacific Northwest and hotter, drier California — the Klamath Basin doesn’t always conform to one regional climate pattern. That makes it difficult to determine whether oceanic conditions like El Niño or La Niña will have an effect on local winter storms in a given year.

O’Neill said there’s not yet a lot of evidence that the storms themselves are behaving differently. There is a hypothesis that as the Arctic warms, the jetstream could shift and alter storm tracks, but the atmosphere is so complex that climate models have difficulty incorporating such large-scale weather patterns. This could change with more science, as evidence is mounting that atmospheric conditions that lead to events like heat waves (which in turn suck more moisture from the landscape) are attributable to this warming-driven jetstream wobble.

Atmospheric rivers like this system, which made landfall in late October, 2021, are expected to increase in frequency and intensity due to climate change. The narrow, moisture-laden storms (called the “pineapple express” due to their origins in the subtropical Pacific) contribute a significant portion of wet season precipitation in Oregon and California. Credit: CIRA/NOAA

Another exception is atmospheric rivers — extreme precipitation events that funnel moisture into the Pacific Northwest and Northern California. They are associated with as much as a third of fall and winter precipitation in Oregon. They are also projected to increase in duration and intensity due to climate change, as a warmed atmosphere becomes laden with more water vapor.

While these drought-busting storms may counteract dryness, they also increase the risk of floods during wet years and soil erosion and sediment loading in wildfire burn areas — especially if warmer temperatures cause them to dump more rain than snow. If the historic atmospheric river and bomb cyclone that occurred in October 2021 had happened a couple months later and made landfall slightly to the north, the Klamath Basin might have been in for disastrous flooding and erosion.

Still, looking at total precipitation or stream output in a given year doesn’t tell the full story. In a basin where so much hinges on the timing of water, a wet winter may appear to mask the woes of an abnormally dry summer, which draws more moisture than usual from forests, lakes and farms.

If a warmer atmosphere can hold more water, the atmosphere over the Klamath Project is at its thirstiest on record. Summer potential evapotranspiration, a temperature-driven measure of the atmosphere’s demand for water over a given landscape, has remained above average for much of the last 20 years, peaking in 2021.

Though they seem like opposite climates, both the Pacific Northwest and California operate on a Mediterranean-style precipitation pattern, with warm, dry summers and cool, wet winters. Climate change is heightening that dichotomy, intensifying both the wet and dry seasons and introducing more stress to the system.

Spring and fall precipitation, which allows more snowpack to make it into waterways and draws snowmelt out later into the dry season, is being sacrificed to the domination of winter and summer. That was certainly the case in Water Year 2021, when a historically dry spring and fall meant that streams and lakes never saw the fruits of a near-average snowpack. Misty Firmin, a meteorologist at the National Weather Service in Medford, said the general trend is indeed for these shoulder seasons to shorten.

“We see summers starting earlier and winters starting later,” Firmin said.

Whether climate change caused the current megadrought is the wrong question to ask, especially since chronic droughts like this have existed in the Western U.S. for thousands of years. Scientists are more concerned with how much worse anthropogenic warming made the conditions of the current dry period.

A 2020 study found climate change responsible for 47% of drought intensity between 2000 and 2018. Comparing the current megadrought to the four worst drought cycles since 800 C.E., researchers learned that warming-driven trends leading to low soil moisture and high evapotranspiration turned a relatively moderate dry cycle into the second-worst drought on record. That’s despite an almost negligible effect of global warming on average precipitation, suggesting that climate change really does its damage after the storms arrive.

“If we didn’t have this warming trend, we’d still be in drought, but it might be moderate to severe instead of exceptional,” said Ryan Sandler, warning coordination meteorologist for NWS Medford.

A sign reads "Endangered farmer can't survive without water" near Tulelake, Calif. on June 14, 2021.

A sign reads “Endangered farmer can’t survive without water” near Tulelake, Calif. on June 14, 2021.

Climatologists have begun to use the word “aridification” in response to this summer’s historic drought in the West and the current megadrought in general. That refers to the long-term drying of a region, driven by frequent, intensifying drought conditions that shift the baseline of water availability on a broad scale. It doesn’t mean that wet, snowy winters will never occur again, but it means extremely dry years will become less the exception and more the rule.

“There’s no longer this absolute baseline where we’re just oscillating back and forth,” O’Neill said. “We’re just becoming permanently drier.”

Despite the uncertainties surrounding climate change’s impacts on precipitation, O’Neill said temperature-driven impacts on the ground are already having an impact on what “normal” means. Multiple years of extremely low percentile measurements in soil moisture, evapotranspiration and streamflow have skewed the average in a negative direction. 

This is especially evident in snowpack trends in the Klamath Basin, where the behavior of snow is particularly sensitive to winter temperatures. The yearly snowpack curve produced by the Natural Resources Conservation Service charts the accumulation of snow as a percentage of a 30-year median of snow-water equivalent. 

Water Year 2022 is the first to plot against the new median of 1991-2020 instead of 1981-2010. The definition of “normal,” which the upcoming snowpack season will be compared to, has already changed for the worse — the Klamath Basin has lost nearly two inches of peak snow-water equivalent. This new normal means a below-average snowpack will translate to an even lower snow-water equivalent than it would have during the last decade, and it takes less snow to reach above-average conditions.

Scott Oviatt, snow survey supervisor for NRCS Oregon, said chronically low snowpack over the last 20 years has reduced the median for nearly all sites across Oregon, particularly the Klamath Basin. While some years have seen exceptionally high accumulations, others have been exceptionally low.

“Especially since 2000, we’ve seen widely variable and extreme conditions, both in terms of precipitation accumulation as well as in terms of snowpack accumulation,” Oviatt said. 

Each month from January through June, NRCS uses this snowpack and precipitation data to model late spring and summer streamflows, forecasting how much water will enter Upper Klamath Lake. The Bureau of Reclamation then uses the NRCS April 1 estimate to decide how much water will leave Upper Klamath Lake — to enter both the Klamath Project and the Klamath River — that summer.

The forecasting model is based on statistics, necessarily relying on data from the past to make its predictions. It identifies analog years — previous years when precipitation and snow accumulation trends appeared similar to the water year in question — and identifies a probable range of future streamflows based on the analog years’ recorded flows.

But because the model relies on past snowpack and streamflow data without incorporating on-the-ground conditions like soil moisture and evaporation, it doesn’t take into account how the snowpack regime has changed. This year, for example, each month’s NRCS inflow forecast to Upper Klamath Lake aligned with the previous month’s driest probability range. That means snowpack translated to less-than-predicted flows into the lake each month.

“It’s not as predictive, statistically or by any other method, to look at as it used to be, because we used to have more trends and more similar years,” Oviatt said.

Part of responding to climate change involves improving those forecast models to give water managers a better estimate of how much of the resource they will have to work with. Oviatt said NRCS is currently developing a machine-learning system that will include soil moisture measurements and other real-time conditions, allowing modelers to better chart the evolution of drought over time.

“Hopefully this will help us with some of the scenarios,” he said.

O’Neill said the shift in hydrology patterns means the past is no longer a blueprint for the future. Managers can either hope a water year behaves like it “should” or have infrastructure and policies in place that help stakeholders live with a new, drier normal.

“The impacts might be the same in the future as they are now,” O’Neill said. “Unless we adapt to them.”

A Reclamation Report

Those who are denied water in the Klamath Basin rarely blame climate change, instead referring to the situation as a “regulatory drought.” But while the federal government does decide how to apportion the water that enters Upper Klamath Lake and has only recently shifted its priorities to allocate water to endangered species, climate change provides less of the resource to work with in the first place.

In 2009, Congress directed the Bureau of Reclamation to produce periodic reports on how global warming is impacting watersheds in the West. Due partially to its unique climate, the Klamath Basin received its own analysis.

Though most broader climatic features like yearly precipitation are expected to see little change in the future, the report revealed an increasingly uneven distribution of water across time and space.

The report found that the Klamath Basin’s mean annual temperature has already increased about 1˚F since the mid-20th century. Climate models estimate an increase of an additional degree early this century, and more than 4.5˚F above the historical average by 2070, depending on whether global emissions reductions targets are met.

Total precipitation in the basin is also projected to increase slightly — about 2% by the middle of this century and 5.5% by 2100 — though the basin’s natural year-to-year variability has caused some models to predict a slight decrease instead. But April 1 snowpack in the basin has declined by 41% since the mid-20th Century, and all models expect it to decline further — dropping another 30 to 40% by the 2030s.

Climate change means more amplified wet and dry seasons, with an increase in winter streamflows but a decrease in spring and summer flows. Despite a slight expected increase in average yearly streamflow, flows during the irrigation season are projected to decrease between 14 and 64% over the coming decades, according to the report. In essence, there may be more water in some years, just not at the right times.

Based on supply equations for the Klamath Project, Reclamation projected that deliveries to Lower Klamath and Tule Lake National Wildlife Refuges would reduce by as much as 43% by 2030, even though total project supply would continue to vary between wet and dry years with little long-term change overall.

Water temperatures are also expected to increase, with the maximum weekly average temperature rising by about 4˚F in the 2030s. That would send river temperatures into a “poor” classification under the Southern Oregon/Northern California Coast Coho Salmon Recovery Plan, putting fish in high-stress conditions more frequently.

A map in the Tulelake Irrigation District office shows the breakout of what is being grown in each field in the district on June 7, 2021, with orange representing unirrigated land.

A map in the Tulelake Irrigation District office shows the breakout of what is being grown in each field in the district on June 7, 2021, with orange representing unirrigated land.

Rodney Cheyne, a fourth-generation farmer in the Klamath Basin, leans on a hammer in his shop located on his farm in Klamath Falls, Ore., on July 27, 2021. Cheyne’s relatives began farming in the basin in 1909, four years after the authorization of the Klamath Project. This year, Cheyne had to partially rely on other sources of income along with farming due to the drought.

The basin’s climate mashup between California and the Pacific Northwest led the models to produce a wider range of outcomes than in other basins. With project supply, for example, some years would be wetter and some drier than normal — but that increased variability wasn’t represented by the report, which describes “little to no change” over the long-term scenario.

The 2021 drought has made many people question whether the West’s water infrastructure and management regimes can withstand climate change. Early Reclamation engineers surveyed the basin during a particularly wet period in the early 20th Century, before federal agencies had to evaluate potential environmental impacts. In fact, most of the Klamath Project’s infrastructure exists to drain water, not to store it.

Though they’re considered natural disasters today, drought cycles drove the evolution of the Klamath Basin that European colonizers encountered in the 1800s — in the past, lower water years helped control bird and fish populations, fostered the growth of wetland plants and kept forests healthy.

In fact, according to a historical streamflow reconstruction from the California Natural Resources Agency, the basin may have endured even longer, more intense dry periods than this one centuries before European settlers arrived. But the droughts that have occurred since colonization — the carving, diking and draining that disconnected the landscape — have been especially hard on the basin’s ecosystems.

The reconstructed annual flow of the Klamath River at Keno, a proxy for the intensity of drought in the watershed throughout history. Data from the California Natural Resources Agency

Lake on the brink

Thirty miles south and 3,000 feet below the rim of Crater Lake lies a lake even more at peril. Upper Klamath Lake is the largest body of freshwater by area west of the Rocky Mountains, and it’s also one of the most polluted. Clear water from a network of picturesque streams and springs takes on a muted, murky brown color once it enters the shallow lake. Massive algae blooms in summer turn the 96-square-mile lake into pea soup. Some say the lake is dying.

If climate change is already altering the comparatively pristine landscape of Crater Lake, overlaying its impacts on the extreme, landscape-scale modifications that have already taken place in and around Upper Klamath Lake make the situation here even more dire.

Mt. Mazama once stood sentinel over the northern arm of prehistoric Lake Modoc, the westernmost reach of a network of vast lakes that pooled in the valleys of the Great Basin during the last Ice Age. These lakes formed almost exclusively from ample precipitation during the most recent glacial maximum, when lower temperatures meant lower evaporation. 

Lake Modoc, however, had more regular inflows thanks to its cradle of frosted volcanic peaks, possibly remaining stable for hundreds of thousands of years before the last Ice Age even began. At its largest, it covered nearly 1,100 square miles of flat lands in the Upper Klamath Basin with as much as 100 feet of water. Upper Klamath Lake contains sediments more than 40,000 years old, and Tule Lake, with some sediment deposits several million years old, is one of a select few ancient lakes on the planet that still exist today.

Upper Klamath Lake from Modoc Point on Friday, June 4, 2021.

Upper Klamath Lake from Modoc Point on Friday, June 4, 2021.

Geologists believe Lake Modoc’s original outlet flowed southeast, into the present-day Pit River watershed, but was plugged by eruptions from the gently sloping Medicine Lake Volcano. The main outlet then shifted to the southwest: the Klamath River near Keno. Eventually, as the region began to warm slowly and the ice sheets retreated beginning at around 12,000 years ago, Lake Modoc gradually dried up into the three shallow lakes that European explorers encountered on their first forays into the basin: Upper Klamath, Lower Klamath and Tule lakes. There all along dwelled two species of sacred, though unpretentious, fish.

The Klamath Tribes have a story about how these fish saved their people. Many generations ago, times were tough. Hunters couldn’t snag game, berries and medicine plants were scarce and salmon didn’t show up like normal. People began to starve and a massive snake started tormenting villages and devouring their inhabitants.

Gmukamps, the Creator, saw the Klamaths’ plight. He charged down from a ridge above the eastern shore of Upper Klamath Lake and slew the evil snake, chopping its body into millions of pieces with an obsidian knife. As those pieces fell into the massive lake, they transformed into large fish with downturned mouths — the C’waam (Lost River suckers) and Koptu (shortnose suckers). They made their homes at the bottom of the lake, feeding on algae and invertebrates in its murky depths.

C’waam and Koptu were a dietary staple of the Klamath and Modoc peoples for millennia, providing one of the first sources of fresh food at the end of a long winter. In the spring, when light, clumpy snowflakes called fish blanket snow began to fall, tribal people knew the fish were heading up the Williamson and Sprague rivers en masse to spawn. After holding a ceremony to honor the suckers’ annual return, they’d catch some with spears or nets, drying and smoking their sweet, white meat or turning it into soup. Year after year, there’d be millions to spare.

A C'waam, front, and Koptu at the Klamath Tribes Hatchery on July 29, 2021.

A C’waam, front, and Koptu at the Klamath Tribes Hatchery on July 29, 2021.

Tribal Chairman Don Gentry said the fish blanket snow still comes almost like clockwork, even in dry years. Sure enough, a gentle snowstorm in late April provided some of the only spring precipitation the Upper Basin saw in 2021. But since the late 1970s, fewer and fewer C’waam and Koptu have answered the snow’s call.

“It still happens, even though there’s hardly any fish coming up,” Gentry said.

With historical estimates potentially in the millions, only about 25,000 C’waam and fewer than 4,000 Koptu now remain in Upper Klamath Lake. Both species were listed as endangered under the Endangered Species Act in 1988, and the Tribes haven’t had a fishery for almost 50 years — instead, they catch only two a year for ceremonial purposes. The number of people alive who have tasted C’waam or Koptu is dwindling, along with the fish.

At first glance, it seems like the suckers are yet another casualty of a warming world. But there’s more to the story: The tricky thing about climate change is that it never occurs in a vacuum. 

Fish populations started declining following the development of the Upper Klamath Basin in the early 20th Century. Huge and distinct sucker populations existed in Lower Klamath and Tule lakes in addition to Upper Klamath Lake. 

The arrival of the railroad to Klamath Falls in 1908 cut Lower Klamath Lake off from the lake system, and the Bureau of Reclamation carved most of it into fields for the newly minted Klamath Project. Tule Lake began drying up soon after the Bureau’s diversion of the Lost River into the Klamath River to make way for farms on the lakebed’s rich peat soils. C’waam and Koptu were almost fully extirpated from these areas, with fewer than 200 adults now surviving in the remnants of Tule Lake. Today, the only somewhat viable population exists in Clear Lake, the reservoir that feeds the Lost River.

In the 1950s, development came for Upper Klamath Lake’s tributaries following the termination of the Klamath Tribes’ federal status, which opened their former reservation lands to ranchers and timber companies. Logging destabilized forest soils, and cattle consumed and destroyed riparian vegetation. The Army Corps of Engineers diked and channelized much of the Sprague River to allow ranching on its dried-up floodplain. Ranchers also drained much of Klamath Marsh, on the Upper Williamson River.

This massive conversion of forests and wetlands to agricultural lands increased the erosion and loading of phosphorus-rich volcanic soils into Upper Klamath Lake. Though the lake was naturally high in nutrients, scientists estimate phosphorus loading has increased by as much as 40% due to human activities. 

Sucker populations would have ebbed and flowed slowly throughout their millions of years of existence in the basin, when droughts lasted for decades at a time and the young Cascades were still violently spewing ash and pumice into the sky. But there were so many of these fish to begin with that, over time, different populations could re-inhabit areas that had dried up or declined in water quality after the droughts ended. 

Given the millennial-scale drying trend, perhaps Tule and Lower Klamath lakes would have eventually dried up on their own in another couple thousand years. But settlement of the basin by Europeans happened far too quickly for the C’waam and Koptu to adapt to the new conditions. Adult suckers are hardy, long-lived fish that survive decently in Upper Klamath Lake, but spawned juveniles haven’t made it through their first summer in the lake since the early 1990s.

“The conditions in the lake that have been caused by land use practices swamp, at least for now, any sort of reproductive event,” said Alex Gonyaw, senior fisheries biologist for the Klamath Tribes.

The Klamath Tribes’ fish hatchery ponds line the bank of the Sprague River on July 29, 2021. The Tribes hope to maintain the genetic stock of wild C’waam and Koptu as their populations in Upper Klamath Lake decline.

Increased phosphorus led to the dominance of two species of cyanobacteria, which bloom and crash several times each summer. With each crash and mass decay of the blue-green algae, the lake’s water quality tanks, stressing out baby fish and leaving them prone to parasites and predation they’d normally be able to survive. And with the majority of the lake’s wetlands drained and diked for agriculture, there’s less filtering of the nutrients entering through its tributaries — and less habitat for the juveniles to rear in.

That’s not to say climate change has no effect on the suckers’ plight. Jacob Kann, an aquatic ecologist with Aquatic Ecosystem Sciences LLC who used to work for the Klamath Tribes, said climate change favors more frequent and intense harmful algal blooms in watersheds around the globe. Cyanobacteria thrive in warm, stagnant water, dominating the system instead of sharing it with other algal species like diatoms and cryptophytes. 

Microcystis aeruginosa, the late-summer cyanobacteria that produces the liver toxin microcystin and closes much of the lake to human use (not to mention emitting a horrendous smell that permeates the shoreline), has especially loved the heat, as algae harvesters on Upper Klamath Lake can attest.

“It’s increasing in the lake,” Kann said. “When they first started harvesting 30 years ago, it wasn’t prevalent. Now, it’s more prevalent.”

The decline of those other algae species, which coincidentally are nutrient-rich food for lake fish including the C’waam and Koptu, may also be making life tougher at the lake bottom. The cyanobacteria that have replaced them, while not directly toxic to the fish, are not nearly as healthy a meal.

“It’d be like eating Cheetos instead of an apple,” Kann said.

Biological opinions require Reclamation to maintain the level of Upper Klamath Lake for sucker shoreline spawning in the spring and for water quality during bloom crashes in late summer — though the agency can still draw the lake down roughly two feet below its historical minimum, thanks to the deepening of the river channel ahead of Link River Dam. Since the dam’s construction, the lake’s hydrograph has shown deeper troughs.

Kann’s research has identified a range of lake levels throughout the summer — higher than the ESA requirements — that could provide better chances of avoiding severe water quality declines and subsequent fish kills. But 20 years of lake level management hasn’t resulted in any successful offspring for suckers.

Gonyaw said that’s because the ESA requirements are the “bare minimum” for the survival of the species — and further, Reclamation has missed one or more of those monthly targets in eight out of the past nine years, making it difficult to prove whether the levels work. But he agreed that the most effective way to improve life for C’waam and Koptu is to reduce the amount of phosphorus entering Upper Klamath Lake’s tributaries and bring nutrient balance back to the lake.

“You’re giving the patient life support just enough to keep them alive, not to recover them,” Gonyaw said. “Recovery would be all the wetlands restored, the water quality corrected and a lake that operated the way it did over the last million years when these fish were evolving.”

Phosphorus reduction can be accomplished through riparian fencing, stream channel and floodplain restoration and beaver dam analogs, among other activities, but climate change threatens to put a damper on those efforts, too. Intense, climate-fueled wildfires like the 2020 Two Four Two Fire and the 2021 Bootleg Fire could cause more phosphorus-rich soil to erode into streams if actions aren’t taken to properly manage forests, cut emissions and mitigate for sediment loading events.

But Gonyaw thinks Upper Klamath Lake can be fixed, which would allow the naturally resilient C’waam and Koptu to better weather future droughts despite long-term hydrological shifts driven by climate change. As far as natural disasters are concerned, they’ve certainly survived worse.

“That’s amazing that they were able to make it through Mt. Mazama exploding, and then we are so harsh on this environment that they can’t make it through us,” Gonyaw said.


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