Below the Current: From Snow to Rain—How Climate Change Is Reshaping the Spokane River

For centuries, the Spokane River’s flow has been shaped by a predictable rhythm: snow falling in the mountains during the winter and melting in the spring to sustain the river through the dry summer months. But now, that rhythm is changing, and with it, the future of the river is being rewritten.

Climate change is altering weather patterns across the globe, and here in the Spokane River basin, the impacts are becoming increasingly clear. Winters are warming, snowpack is shrinking, and rain is replacing snow in many parts of the watershed. This shift from a snow-based system to a rain-dominated one is reshaping the river’s flow patterns, threatening water quality, and challenging the ecosystems that depend on it. 

HISTORICAL PRECIPITATION PATTERNS 

For centuries, the Spokane River relied on a predictable cycle: snow accumulated in the mountains during winter, then melted slowly in the spring, sustaining river flows through the dry summer months. This snowpack acted as a natural reservoir, releasing water gradually and ensuring a steady flow that supported ecosystems, recharged aquifers, and maintained water quality.

Winters in the region were traditionally cold and snowy, with Spokane an average annual snowfall total of 45 inches. The surrounding mountains stored even greater amounts of snow, which melted progressively from the lowlands to the highest peaks throughout the spring. This steady melt fed the river and its tributaries, creating the powerful spring flows that make the Spokane Falls a breathtaking sight every year.

This seasonal rhythm was more than just a natural process—it shaped the culture and economy of the region. Indigenous tribes gathered each June at the falls for salmon fishing, relying on the river's flow to sustain their communities. Even today, the falls remain a central symbol of Spokane, drawing visitors to Riverfront Park every spring.

The river's spring surges have long been critical for the river’s ecosystem. These flows flush sediments, dilute pollutants, and provide critical habitats for fish like trout and salmon. They also create opportunities for whitewater recreation, attracting kayakers and rafters to play in the rapids such as Bowl & Pitcher and Devil’s Toenail.

But this dependable cycle is changing. Warmer winters mean less snow and more rain, disrupting the natural rhythm that has sustained the Spokane River for generations. As spring flows diminish, the impacts ripple across the watershed.

CLIMATE CHANGE AND PRECIPITATION SHIFTS

Mica Peak and surrounding area, which feeds Hangman Creek, taken on January 13, 2025 shows the lack of snowpack in the lower elevations.

The Spokane region is already experiencing the impacts of a warming climate, and the changes are reshaping the river’s flow. As temperatures rise, more winter precipitation is falling as rain instead of snow. This shift in precipitation, coupled with earlier snowmelt, is altering the timing and intensity of streamflow in the Spokane River—even if the total annual streamflow remains similar to historical levels.

These changes are not hypothetical; they’re well-documented and ongoing. Between 1955 and 2016, 90% of snow monitoring sites in the American Mountain West recorded significant declines in snowpack (Mote et al., 2018).  Locally, this trend is evident in reduced snowfall and warmer winter temperatures. As of the second week of 2025, snowfall in the Spokane region is only about half of what’s typical for this time of year, with rain increasingly replacing snow in lower elevations.

IMPACTS ON THE SPOKANE RIVER

Snowpack, which acts as a natural water storage system, is shrinking. When precipitation falls as rain instead of snow, it enters rivers and streams immediately as runoff rather than being stored for gradual release during the spring and summer. This results in higher stream flows during the winter and lower flows during the spring, when native fish need this water most.

A shift in precipitation falling as rain instead of snow leads to a decrease in the amount of water stored in the mountains as snow that would otherwise enter the stream system later during the spring and summer months. As a result, more water flows out of the watershed earlier in the year, leading to earlier and longer summer-low flows in rivers and streams. The impacts on streamflow from the transition from rain to snow are already noticeable in the Spokane watershed in certain individual years (Abatzoglou 2016) and over a multi-year period (Porcello et al., 2017). 

From 1971–2000, flows peaked on the Spokane River during the month of May. Modeling predicts that by mid-century we will see two peaks in flow: first in February and then again in April. The February peak arises as a result of more precipitation falling as rain in the cool season, immediately running off into the system. These mid-winter rain events include additional runoff caused by rain on snow events, where warm rain falls on existing snowpack, that can speed up melting and reduce snowpack available for spring. 

Water Quality Concerns

Hangman Creek during a high runoff event is visibly thick with sediment.

Water quality is a critical concern as the watershed shifts from a snow-dominated system to a rain-dominated system. An increase in the frequency of rain-on-snow events creates a surge of runoff that carries sediment and pollutants into the river. Combined with heavier and more frequent winter rainstorms, this situation is intensifying stormwater pollution risks to the river.

During rain-on-snow events, the rapid melting of snow can overwhelm natural and man-made drainage systems. The fast-moving water picks up sediments, including dirt, silt, and organic matter, from the landscape and deposits them directly into the river. This sediment load can cloud the water, harm aquatic habitats, and disrupt the lifecycle of sensitive species like trout and salmon that rely on clean, oxygen-rich water. One example of this can be seen at the confluence of the Spokane River and Hangman Creek during and after storm events in the Hangman Creek basin. 

Stormwater runoff during these events also carries a cocktail of pollutants, including oils, heavy metals, fertilizers, and pesticides from urban and agricultural areas. The combination of sediment and stormwater pollution can exacerbate nutrient loading, which fuels harmful algal blooms and depletes oxygen levels in the water, further threatening aquatic life. 

Redband Trout

Changes to flow patterns are likely to have substantial impacts to the native redband trout populations on the Spokane River due to longer periods of warming and reduced cold water habitat. The Spokane River below Sullivan Road is heavily influenced by inflow from the Spokane Valley Rathdrum Prairie Aquifer, which helps keep some sections cooler in the summer. However, projections of reduced surface flows would result in reduced carrying capacity for Redband trout and an anticipated increase in predation from species that thrive in warmer water temperatures. Of particular concern to the viability of Redband trout is the projected earlier low-flow period beginning as early as May, rather than later in the summer.

Juvenile redband trout in October. Photo by Tim Connor.

Projected reduced flows below Post Falls Dam could result in warmer water temperatures that benefit smallmouth bass (a non-native species) and approach the upper lethal temperature range for redband trout. Redband trout generally prefer stream temperatures less than 70 degrees Fahrenheit (Wydoski and Whitney 2003) and start to struggle in waters at 71.6 °F and above (Behnke 1992). During the hot summer months, when flows are reduced, much of the river is too warm for redband trout to survive. Earlier peak-flow and reduced summer flows would further decrease viable rearing habitat for redband trout. Additionally, reduced flows in late May/early June could dewater trout eggs, further reducing trout populations. Spawning generally commences at the beginning of April, and emergence occurs near the end of May, but a decrease in flow during the incubation period would cause the water levels to fall below the fish nests, drying the eggs and decimating the trout populations. 

Whitewater Recreation

In the springtime, the high Spokane River flows create a whitewater playground for recreational activities like kayaking and rafting, and supporting multiple rafting businesses. Historically, flows supported whitewater recreation through the lower portion of the river (between Spokane Falls and Nine Mile Reservoir) through the month of June. With earlier spring high flows, and an earlier, extended summer low flow period, whitewater opportunities may be limited to a short period in May when flows are high enough to safely navigate the rapids. 

LOCAL AND REGIONAL RESPONSES

In the face of these challenges from climate change, there are some local and regional efforts underway to safeguard our water resources for the future. One significant example of these efforts is the City of Spokane’s water conservation rules, designed to keep more water in the Spokane Valley-Rathdrum Prairie Aquifer, which sustains the river’s flow during dry periods. By reducing the amount of water pumped from the aquifer during the peak watering season, these rules help maintain higher aquifer levels, ensuring that the river continues to flow, even in the hottest months. These inflows from the aquifer are crucial for maintaining water temperatures that can support native fish life. 

Example of a swale installed by the City of Spokane that allows large volumes of stormwater to slowly infiltrate the soil, rather than get discharged directly to the river.

Additionally, the region has begun to invest in green infrastructure including bioswales, rain gardens, and stormwater retention basins, to slow and filter runoff before it reaches the river. Significant investment in climate resilient green infrastructure will significantly reduce the pollution impact stormwater and runoff have on the water quality of the Spokane River.

While these efforts are making an impact, there is still more to be done. Beyond city limits, regional collaboration is key to addressing the Spokane River’s challenges. Partnerships with neighboring municipalities, tribal nations, and conservation groups can help align water use practices across the watershed, creating a united front in protecting the river. As climate change alters the hydrology of the Spokane River basin, we must continue to expand water conservation programs, invest in green infrastructure, and advocate for policies that prioritize keeping water in the river. 

CONCLUSION

The Spokane River is a vital part of the region’s identity, economy, and ecosystem. However, as climate change continues to shift precipitation patterns from snow to rain, the river’s future faces unprecedented challenges. From reduced snowpack and altered flow cycles to water quality concerns and ecological stress, these impacts underscore the urgent need for action at every level.

But there’s hope. Our community and policymakers are beginning to recognize the importance of adapting to these changes. By advocating for sustainable water management policies, we can work together to build a more resilient future for the river. Now is the time to act. The Spokane River needs all of us—our creativity, our dedication, and our willingness to make a difference. The Spokane River has shaped our lives for generations. Now, it’s our turn to shape its future.

Together. For the River.

Resources

Abatzoglou, John T. "Water year 2015: A glimpse of our future?" Coeur d’Alene, Idaho: Plenary presentation prepared for the Spokane River Forum Conference. March 23, 2016.

Behnke, Robert J. "Native trout of western North America." American Fisheries Society monograph (USA). no. 6. (1992).

Gonzaga University Climate Institute, "Spokane Climate Project" (2022). Climate, Water, and the Environment Research. 1. https://repository.gonzaga.edu/climateresearch/1

Porcello, John, Walter Burt, Jacob Gorski, and Ty Wick. 2017. “Climate Change and Summer Streamflows: Climate Change Influence on Summer Streamflows: Unanticipated Discovery While Studying Other Influences.” In The Water Report: Water Rights, Water Quality & Water Solutions in the West. EnviroTech Publications, edited by David Light and David Moon, Eugene, Oregon. Issue #166. December 2017.

Wydoski, Richard S., and Richard R. Whitney. Inland fishes of Washington. American Fisheries Society, 2003.