Tourists driving along the Grand Loop Road between Madison Junction and Mammoth Hot Springs in Yellowstone National Park might pass by one of the park’s most unique thermal features without a second glance.
Nevertheless, Beryl Spring has been determined to make its presence known, even if it’s though acting up and being ornery.
Anyone driving by will hear the roar of steam emanating from the 25-foot-wide, 8-foot-deep pool and feel its spray as they move along the boardwalk. Sharp-eyed observers will notice how Beryl Spring has improved the ambiance, as its spray has tinted the untreated wood of the boardwalk a lovely shade of blue.
Beryl Spring rarely appears on the list of the best thermal features in Yellowstone, but it’s one that’s delighted visitors, intrigued scientists and frustrated managers since the park’s inception.
“Beryl Spring is a bridge over troubled waters,” said Mike Poland, scientist in charge of the Yellowstone Volcano Observatory. “Its nature is super complex and not incredibly well-known. It’s pretty interesting as a hot spring and a piece of Yellowstone’s history.”
Blue Bother
Beryl Spring is one of the hottest hot springs in Yellowstone, with an average temperature of 196 degrees. The surface of the spring is constantly churning as steam and volcanic gases thrust through the water and out into the air.
"I've always thought Beryl Spring is one of the coolest features in Yellowstone - even though it's not cool at all," said author and lifelong Yellowstone employee and enthusiast Jeff Henry. "Its temperature is actually above boiling for its elevation."
When the U.S. Geological Survey (USGS) conducted its 1883 expedition into Yellowstone, the bluish-green water reminded them of the gemstone beryl. Thus, Beryl Spring.
Beryl Spring has been a source of wonder and frustration along the Grand Loop Road ever since. Poland said the park’s construction crews had to get creative when building by Beryl.
“It was an engineering nightmare,” he said. The park kept trying to deal with this area. They couldn't go around it because the canyon is pretty narrow right there, but Beryl Spring kept making this difficult.”
In 1928, a hard-surface road was built in the narrow corridor adjacent to Beryl Spring. Construction equipment breached a thin surface of sinter crust, which dropped and muddied the spring’s water and led to new hot springs forming under the road.
Attempts to cap the new hot springs with concrete failed as the acidic volcanic gases ate away at the caps. Finally, on Sept. 18, 1942, the road caved in and left a broken, partially flooded section of a vital transportation corridor.
Three truckloads of obsidian and six truckloads of clay were dumped into Beryl Spring in the hope that it would plug up or mitigate the impact of the spring. That didn’t work either.
Then, the force of the 1959 Hebgen Earthquake changed the behavior of Beryl Spring dramatically. A pipe installed to divert the pool’s caustic water was discharging 34 gallons of water every minute.
Robert Fournier, a USGS geochemist with a long legacy of scientific contributions in Yellowstone, studied Beryl Spring to find a solution to the persistent road issues. The National Park Service implemented his solution in 1962.
“Ultimately, they built a container for the feature under the road and built a bridge over that container,” Poland said. “It’s like a causeway or viaduct with the thermal feature contained by a concrete box underneath the road.”
The container allowed the Beryl Spring’s water level to rise to accumulate safely while venting its steam away from the road, restoring some lost luster to the spring and safety to the road.
That complex infrastructure is still in place today, and the park’s road and maintenance crews are probably hoping they won’t have to revisit it anytime soon.
Complex Chemistry
Even in the dynamic, ever-changing environment of Yellowstone, there’s something unique about Beryl Spring. Poland said the pool has a unique chemistry, which explains its distinct fragrance.
“Beryl Spring is known for having a complex chemistry,” he said. “The vast majority of those vapors are certainly steam, but some other things are mixed in there, like hydrogen sulfide. That explains the rotten egg smell you get when you visit.”
But Beryl Spring's unique nature goes much deeper. Poland said a team of scientists from the University of Wyoming (UW) determined that it draws from a different source than most of the other thermal features in Yellowstone.
“The UW scientists determined that the composition of the waters and gases coming out of Beryl Spring has similarities to sedimentary rocks that are way beneath the ground,” he said. “That suggests that the waters have circulated very deep, beneath all of the volcanic material and into the much lower sedimentary rocks.”
As boiling water and steam circulate through Beryl Spring’s subterranean plumbing system, it absorbs some of the chemistry of the rocks on its way to the surface, emerging as high-chloride water with a nearly neutral pH. That’s why the spring has been so bothersome, beautiful, and baffling.
“There’s a lot of chemical reaction and fluid behavior happening down there, under the surface,” Poland said.
Beautiful Blue Boardwalk
Beryl Spring has a proclivity for beautifying its surroundings, which makes it a popular spot between Madison and Mammoth.
Nearly every snow coach driving along the Grand Loop Road stops at Beryl Spring. The constant flow of steam in the heavily shaded chasm freezes on the branches of nearby trees as wind-blown rime frost, creating beautiful and dramatic “ghost trees” that are a popular photo-op.
"It produces some of the most dramatic 'ghost trees' in the park," said Henry. "I have tried and tried to get just the right combination of light and other circumstances to create the perfect photograph of that phenomenon but have never totally succeeded. I still stop at Beryl Spring frequently when I pass by in the winter to admire both the spring and those ghost trees.
Then, there’s the blue tint to the wood along the Beryl Spring boardwalk. Wooden posts installed along the bridge have been stained to a lovely shade of blue, reminiscent of the gemstone that gave the spring its name.
The complex chemistry and subsurface shenanigans of Beryl Spring might explain the blue beautification of the boardwalk. However, if there is an explanation, Poland doesn’t know it.
“I’m sure it depends on what’s in the wood, but I don't know what is turning it blue,” he said.
Beryl Spring isn’t going anywhere. It has defied multiple attempts to make it conform to the development of Yellowstone National Park and will defiantly bubble, boil, and billow along the Grand Loop Road as it pleases.
“Beryl Spring has been the topic of a lot of research, but we still don’t know that much about it,” Poland said. “Some places, like the features around the Upper Geyser Basin and Mud Volcano, have consistent chemistries, while others, like the Norris Geyser Basin, have mixed chemistry. Beryl Spring is an excellent example of mixed, complex chemistry that makes Yellowstone so dynamic.”
Contact Andrew Rossi at arossi@cowboystatedaily.com
Andrew Rossi can be reached at arossi@cowboystatedaily.com.