The Lava River Cave near Bend, Oregon, is part of the Newberry National Volcanic Monument, which is managed by the United States Forest Service. At 5,211 feet (1,588 m) in length, the northwest section of the cave is the longest continuous lava tube in Oregon. While the cave's discovery in 1889 was officially credited to a pioneer hunter, the presence of obsidian flakes near the cave has led archaeologists to conclude that Native Americans knew about the cave long before settlers arrived in central Oregon.
Geology The eruption which formed the Lava River Cave occurred about 80,000 years ago. The source is believed to be near Mokst Butte southeast of the entrance. The same volcanic flow that formed the cave underlies much of the Bend area and almost reaches Redmond, Oregon. However, the specific vent that created the cave has been buried by several younger flows. The Lava River Cave was created by lava flowing downhill from a volcanic vent. The lava flowed northwest from the vent toward the Deschutes River. The flow began as a river of lava flowing in an open channel. Eventually, a lava crust solidified over the top of the flowing lava. This formed a roof over the river, enclosing it in a lava tunnel or tube. When the eruption from the vent stopped, the lava drained out of the tube leaving a lava tube cave behind. After the cave cooled, a section of its roof collapsed. This collapsed section provided the entrance to both the uphill (southeast) and downhill (northwest) cave sections. The area around the Lava River Cave receives about 18 inches (46 cm) of precipitation per year. Over the centuries, water from rainfall and snow melt has seeped down through the soil and cracks in the cave roof depositing sand on the cave floor. Small rivulets of water carry the sand downhill, plugging the far end of the cave with sediment. As a result, it is unknown how far the cave actually extends beyond the sand plug.
Environment
The Lava River Cave is located 12 miles (19 km) south of Bend on the east side of Highway 97. It is part of the Newberry National Volcanic Monument, which is managed by the Forest Service as part of the Deschutes National Forest. The forest surrounding the cave entrance is dominated by large ponderosa pine trees with sagebrush, manzanita, bitterbrush, snowbrush, and chokecherries as the main ground cover. Along the short path leading from the forest floor down to the cave entrance, visitors will also find serviceberry, false Solomon seal, squaw currant, Oregon grape, and small willow trees. Animals common in the forest around the cave include golden-mantled ground squirrels, chipmunks, western gray squirrels, porcupines, weasels, pine martens, and mule deer. In 1991, park personnel observed a full-grown cougar run out of the cave entrance area, but that was a single sighting. There is also a wide range of resident and migratory bird species common to the area. Small resident birds include wrens, robins, juncos, thrushes, woodpeckers, sapsuckers, red-shafted flickers, and ruby-crowned kinglets. Larger birds include great horned owls, red-tailed hawks, vultures, and a few golden eagles. Forest Service biologists have identified several species of harvestmen, worms, centipedes, and millipedes that live inside the cave. The harvestmen within the cave are Taracus marchingtoni, a newly described species endemic to the region.
There are also mice and bats that live in the cave year around. The cave's bat population is relatively small and the bats are very shy so visitors rarely see them. In fact, bats usually remain in hibernation until July, and when active they are nocturnal so they are asleep during the day when the cave is open. If a bat is sighted, the Forest Service recommends that it be left undisturbed. Waking it from hibernation is extremely stressful, and can cause the bat to die from the sudden expenditure of energy.
History The presence of obsidian flakes near the cave has led archaeologists to conclude that Native Americans knew about the caves long before any pioneers arrived in the Oregon Country. The first recorded discovery is credited to a local settler named Leander Dillman, who found the cave opening on a hunting trip in 1889. Legend has it that Dillman found the cave entrance while following a wounded deer. After its discovery, he used the cave to cool his venison. The cave acquired its name from a 1923 geology study published by Ira A. Williams. The study also provided the first map of the cave. In 1938, the highway department announced an effort to resume digging efforts originally started by Emil Long to extend the cave beyond the dirt choke. It was speculated the cave could go all the way to Benham Falls. In 1926, the Shevlin-Hixon Lumber Company donated the 22.5-acre (91,000 m2) site around the cave entrance to the State of Oregon for a park. In 1981, the cave and above ground park area were acquired by the Forest Service as part of a land exchange with the State government. In November 1990, the cave was incorporated into the Newberry National Volcanic Monument. However, it is still managed by the Forest Service along with the rest of the Newberry monument area.
Cave tour
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