This does not look like the kind of place I would expect to find in a place called Battle Ground, Washington. Nor the kind of place I would associate with a volcanic eruption. Battle Ground Lake is too peaceful, beautiful, and lush. And, on one of the hottest days of Summer 2018 so far, it was a place full of happy human beings enjoying the simple pleasures of a cool lake in a state park. Listen:
There were hundreds of people on one side of the lake at a small beach area, picnic tables, a dock, and restrooms. Everyone seemed happy. It was as if everyone checked any grouchiness and stress at the entrance gate. Whether people arrived with picnic coolers, silly inflatable floating devices, swim goggles, kayaks, stand-up boards, beach chairs, or paperback books, everyone was enjoying themselves and--it seemed to me--happy others were enjoying themselves. Even when, late in the afternoon, someone cranked up their boombox with classic rock and roll hits--no one glowered or complained. A few swimmers were actually dancing to "Eye of Tiger" as they stood waist-high in the water on the concrete boat ramp.
The sounds from the shore created a pleasant summer din as my friend and I swam the perimeter of this 27-acre lake. We rested on logs floating along the lakeshore. We watched very small fish take an interest in our wiggling toes (big, fat worms!). Near the rope swing, we dog paddled to watch young teens scramble up the steep muddy hill and then swing out over the water for a plunge that looked so fun and sounded so refreshing it brought a smile to my face.
Battle Ground Lake is named for a battle that never took place near present-day Battle Ground in 1855--a non-battle involving Klickitat tribes living on the Lewis and Cowlitz Rivers, U.S. troops stationed at Fort Vancouver, and "friendly fire" mistakes. The origin of the town and lake name is not half as interesting as the origin of the lake itself.
According to the U.S. Geologic Survey, Battle Ground Lake in Washington, a maar volcano, was formed when magma encountered water and blasted through a 100,000 year old lava flow. This is one of the youngest volcanoes in an area known as the Boring Lava Field, which extends east and north from the Vancouver-Portland area. Battle Ground Lake is one of 80 volcanic vents and associated lava flows evident in the area. Geologists believe many other vents were buried during the Missoula Floods.
The map below shows some of the Boring Volcanic Field. Battle Ground Lake is not shown here but is located in the orange areas at the top of the map, east of the I-5 and on the south side of the East Fork of the Lewis River. More on the Boring Volcanic Field from the USGS here.
Map image from USGS, Everts et al 2009
The skyline in this region and its 1980 eruption is still so fresh in my memory that I have to remind myself that, even though Mount St. Helens transformed the local landscape, Mount St. Helens was not the only show in town.
The lake I was swimming was created about 100,000 years before Mount St. Helens' 1980 eruption. I knew I was swimming in an older landscape. I was swimming in a 60-foot deep lesson in local geology. I was swimming the cool refreshing legacy of ancient magma and boiling water.
Evidence of Battle Ground Lake's geologic history is easy to see if you walk/hike the 1-mile long Lower Lake trail in the park. Here is a chunk of volcanic basalt with vesicles formed by trapped gas. The Lower Lake trail winds through mature evergreen forest--and offers plenty of shade, access points to the lake and the rope swing. (Photo by M.M. Ruth)
For more information, WA State Park website or Washington Trails Association website for a description of the Lower Lake trail. More on the Boring Volcanic Field from the USGS's Cascades Volcanic Observatory here.