My friends and I, optimistically but naively, brought our fly fishing gear on a backpacking trip to the White Clouds in late September.
We were looking for more secluded places, perhaps a little further from Boise, with perhaps a little more difficult hiking to escape the madding crowds.
The Ocalkens Lakes seemed to fit the bill: the trailhead is about 27 miles east of Stanley, and the hike was about 4.5 miles, with an elevation gain of 2,000 feet to Ocalkens Lake #2 at 9,200 feet.
Exactly what we were looking for.
Until we get there.
We were shocked and disappointed to find that Ocallens Lake #2 was almost dry.
Some water was still a few inches deep, but we were able to cross the muddy lake bed to the other side.
Certainly no fishing there.
We were able to find Ocallens Lake #1 a few hundred meters away. It’s a much smaller lake (more like a pond) but apparently quite deep on one side. The water was a shade of green that matched that of the Chicago River on St. Patrick’s Day.
We saw a few fish rise, but none hit the flies we cast there.
As we sat around eating our freeze-dried dinners and sipping whiskey that evening, we began to speculate as to why Ocalkens Lake #2 was almost dry.
I’m going to blame the whiskey, but our main theory was that the 2020 Stanley earthquake opened a fissure under the lake and drained it into an underground aquifer, which explained why Slate Creek was still flowing with water all the time. at the bottom of the pool.
After all, the 6.5 magnitude earthquake caused sediments near the entrance to Stanley Lake to liquefy, causing a popular beach and fishing area to collapse. Earthquakes are also known to create lakes (see Quake Lake in Montana).
Or perhaps there is a simpler, less dramatic explanation.
“If I had to guess, I would say Ocalkens Lakes #2 are limited,” Tyler King, a research hydrologist at the U.S. Geological Survey’s Idaho Water Science Center in Boise, wrote to me in an email. “Conceptually, I assume that the lake loses water to the stream by surface flow and to the subsurface (i.e., to groundwater) by infiltration. When losses exceed contributions, lake levels drop.
In other words, the lake was not filled with enough water during the rainy season to keep it filled throughout the summer.
And it seems that this has dried up since at least 2016.
According to the Idaho Department of Fish and Game’s 2016 Fisheries Management Annual Report, the survey team was able to see the entire bottom of Ocallens Lake #2.
Idaho Fish and Game had stocked Ocalkens #2 until 2014, but the water level was so low in 2016 that Fish and Game didn’t even bother to stock the lake.
“The lake used to be stocked with cutthroat trout pretty consistently,” according to Martin Koenig, sportfishing program coordinator for Fish and Game. “However, biologists surveyed the lake in 2016 and noticed that it was already 1.5 feet below full level and most of the lake was less than 5 feet deep. Despite stocking only two years previously, no fish were observed during the survey, suggesting the lake is too shallow to support them at this stage. With such a shallow lake, it is very difficult for trout to survive the winters.
Climate change
So who is the culprit?
Anna Bergstrom, an assistant professor in the geosciences department at Boise State University, thinks the culprit is likely climate change.
“Without doing too much research on this, I would tend to agree that this is a problem related to climate change rather than a specific event,” Bergstrom wrote to me in an email. “Many changes have been documented in alpine and mountain lakes, including changes in thermal regimes, chemistry, and the types of aquatic organisms they can support. It’s entirely reasonable to imagine that warmer temperatures and changing precipitation could cause lakes to shrink or become wetlands.
As Koenig noted: “Aerial photos today show many open meadows that were once lakes on old USGS topo maps. »
Bergstrom’s colleague at Boise State, geosciences professor Lejo Flores, added that other factors could also play a role, such as a decrease in ice cover during winter and a shift from predominantly snowy runoff to spring and autumn rains.
Even plant cover could play a role. Fewer trees mean less shade, and warmer temperatures without shade mean more evaporation during hot months.
King of the USGS pulled several years of precipitation data for the Salmon River watershed, where the lake is located.
Data shows that 2024 was one of the driest years on record, second only to 2021. According to the data, 2024 is in the 17th percentile (83% of years expected to have more precipitation) compared to the 42 years on record . from 1982 to 2024.
The lake was also nearly dry in 2021, according to images taken by the USGS Earth Explorer’s National Aerial Imagery Program.
Groundwater flow
As for why Slate Creek was still flowing profusely, Bergstrom suggested that surface and groundwater are closely related, so that even if there isn’t much water on the surface, there can still be have underground groundwater feeding Slate Creek.
“This nice flat area would make a good recharge area for the groundwater system,” Bergstrom wrote. “Then when you go downhill and you have much steeper slopes, they can intersect the groundwater flow paths and the groundwater can flow back into the streams and become surface again, supporting higher flows.”
King gave me a metaphor that makes sense of the concept.
“Think of a strainer placed in a water fountain,” King wrote. “If the water cooler is full enough, there is water in the strainer. As the water cooler empties, the strainer dries out.
There may still be water at the bottom of the cooler, so when you open the drain plug the water will still flow out (Slate Creek).
“This intersection of the water table and the land surface allows the stream to flow as long as there is water in the aquifer,” King wrote. “It is plausible that there are flow paths beneath the lake that support the stream even once the water table drops below the lake bottom elevation.”
I still like my whiskey-induced idea that an earthquake opened a fissure, but I’m going to follow the experts’ theories on this one.
Sadly, this looks like an example of climate change taking away yet another place we love.
