Preparing for snowmelt and runoff

by Stephanie Conrad, Hot Springs County Emergency Management Coordinator

As winter settles in and the snow continues to accumulate in the surrounding mountains, it’s a good time to revisit the snowpack and runoff conditions that directly impact Boysen Reservoir. While snowstorms typically ramp up in March and April, it’s crucial to monitor these patterns early—so the community and agencies alike can prepare for what’s ahead.

It’s been a few years since we’ve delved into the details of how snowmelt from nearby mountain ranges feeds into Boysen Reservoir and the Big Horn River, so the Hot Springs County Emergency Management Office thought it’d be helpful to update the public with some new information for this season.

What is a SNOTEL?

One of the key tools in monitoring snowmelt is the SNOTEL (Snow Telemetry) system, a network of automated weather stations that collect data on snowpack and other climatic factors in remote mountain areas. The SNOTEL network is operated by the Natural Resources Conservation Service (NRCS), a division of the U.S. Department of Agriculture (USDA). The data gathered by these stations allows agencies to predict snowmelt, runoff volumes, and ultimately how much water will flow into Boysen Reservoir.

In the case of Boysen, four SNOTEL stations are key to understanding the snowpack feeding into the reservoir: Deer Park, Townsend Creek, South Pass and Hobbs Park.

These stations monitor snow levels in the mountain ranges that drain directly into Boysen. By tracking snow water equivalent (SWE)—the amount of water contained within the snowpack—these stations help predict how much runoff will make its way to the reservoir as temperatures rise.

Current Snow Water Equivalent and Future

Predictions

At present, the snow water equivalent data from the four SNOTEL stations provide valuable insight into what we can expect for runoff, though it’s important to remember that conditions will likely change as we move further into March and April. Snowmelt is inherently unpredictable, with the greatest variability in runoff occurring when large spring storms come through.

The current snowpack levels indicate there is a significant amount of water stored in the snow, but it’s too early to determine exactly how much will eventually flow into Boysen. Snowpack will continue to accumulate, and monitoring will intensify as we move into spring.

Reservoir Storage and Management

The U.S. Bureau of Reclamation plays a central role in managing Boysen Reservoir, focusing on monitoring inflows, ensuring adequate storage for agricultural, recreational, and power generation needs, as well as managing flood control.

At present, Boysen Reservoir is sitting with approximately 14 feet of lake depth that still needs to be filled as the runoff begins. The Bureau of Reclamation’s goal is to fill the lake by the end of the runoff season. To do this, they track the inflows and adjust releases from the dam accordingly, all while maintaining flood control operations.

A detailed plan, taking into account the snowpack, runoff forecasts, and inflow data, will be finalized in the coming months. This plan will guide the Bureau of Reclamation’s decisions on dam releases, aiming to fill the lake to optimal levels by the end of the spring runoff season.

What’s Next?

As we move through February and into March, agencies will continue to monitor snow levels and runoff predictions. The next update, from Hot Springs County Emergency Management, on snowpack and runoff expectations will be released in March, as the snow accumulates and the melt begins.

For now, we remain cautiously optimistic about the spring runoff, keeping a close eye on snowpack levels, reservoir storage, and the weather to ensure that Boysen Reservoir is ready for the coming season. Stay tuned for updates as we track these critical water conditions through the spring and summer months.