Recreation

Lava River Cave, located approximately 12 miles south of Bend on Highway 97, is open from mid-May to mid-September. The trail is approximately 2.2 miles round-trip from the parking lot to the end of the trail within the Cave. Entrance to Lava River Cave is not permitted outside of the operating season and hours in order to protect critical bat habitat.

A Volcanic Story

Lava tubes are formed in flows of pahoehoe (pa-hoy-hoy) basalt. This type of lava is very fluid and moves readily downslope. Lava tubes are crusted over channels which conduct lava to the advancing front of the flows. Crust formation starts near the vent where the lava spews from the earth, then gradually progresses downslope along the lava stream. The crust is first a thin ledge-like protrusion extending inwards from the sides of the lava channel. The roof gradually thickens as surges of lava break through and spread out as thin layers. Additional lava linings to the underside of the roof provide still more support. When the molten river of lava stops, the tube drains leaving an empty “cave.”

Lava tubes are discovered when a part of their roof collapses and exposes an underground cavern. Some reasons for roof collapse are cooling and shrinkage after the lava flows out of the cavern, freezing water that eventually dislodges rocks, or severe earthquakes.

Lava River Cave extends in two directions from the entrance. The main tube is the longest known intact lava tube in Oregon. It trends in a northwesterly direction for about 6,000 feet with a gradual downhill slope toward the Deschutes River. The southeasterly extension of the cave is about 1,560 feet long. This section is closed to the public due to loose and dangerous rocks, as well as, to provide undisturbed habitat for wildlife that rely on the cave ecosystem.

The sparsity and spaciousness of Central Oregon’s volcanic landscapes creates striking beauty both above and below ground. Newberry National Volcanic Monument known for its diverse volcanic features, is well named. Large areas are covered by relatively recent basalt lava flows. Great tunnels wind through many of these flows suggesting that awesome forces of nature were once at work. These ancient natural tunnels called tubes are one of the area’s most interesting secrets. Lava River Cave is an outstanding example of these ancient lava tunnels.

Leave nothing but footprints. Take nothing but pictures.

History

Archaeological research has produced a wealth of information regarding the prehistory of Central Oregon, including in the general vicinity of Lava River Cave. Early occupation of Newberry Crater, located 23 km southwest of Lava River Cave, has been dated to 10,500 B.P. At that time, groups likely subsisted on a diverse array of resources and were highly mobile. Archaeological research at the Paulina Lake Site in Newberry Crater resulted in documentation of the oldest known habitation structure in the region, dating to 9,500 B.P. Excavations at Lava Island Rockshelter, located 10.5 km northwest of Lava River Cave, suggest that this site was a hunting camp that had been occupied as early as 10,000 B.P.

The catastrophic eruption of Mt. Mazama approximately 7,700 years ago marked a dividing point in both natural and cultural regional histories. Groups that resettled the area after the Mazama ashfall increasingly relied on stored fish and plant resources. Groups utilizing the upper Deschutes River following the Mazama eruption appear to have shifted to more of a collector economic system, and regional populations rose.

From around 2,000 B.P. until contact, the region likely saw a drop in population as groups increasingly clustered around the Columbia River. Subsistence during this time period continued to be focused on hunting, gathering, fishing, and stored resources. Technological strategies shifted as the bow and arrow was introduced into the region.

The location of Lava River Cave in Central Oregon places it at the confluence of three geographic areas: the Northern Great Basin, the Southern Columbia Plateau, and the Cascade Range. Ethnographically known groups who utilized these areas include the Northern Paiute, as well as the Tenino/Tygh and the Molalla who were both semi-sedentary groups inhabiting winter villages. The Molalla were broad spectrum hunter-gathers and the Tenino/Tygh subsistence economies were dominated by fish, primarily salmon.

Euro-American exploration of Lava River Cave can be traced back to 1889. It was first known as Dillman Cave, named after Leander Dillman, who discovered it while hunting. Dillman was a local stockman and trapper who lived nearby and used the cave’s year-round 42 degrees (F) temperature as a natural refrigerator to cool his venison.

For 32 years the cave was known as Dillman’s Cave, but in 1921 Dillman was convicted of a crime and the cave’s name was changed to Lava River Cave. The name is derived from a geologist’s study of the cave in 1923. Ira A. Williams called the cave “The Lava River Tunnel.” His works also provided us with the first known map of the cave.

In 1926, possibly due to William’s writings on the beauty of the area being threatened by logging operations, Shevlin-Hixon Lumber Company deeded 22.5 acres of land surrounding the entrance to the State of Oregon for a state park. In 1981, the Forest Service acquired the cave as a recreation site in a land exchange. The Deschutes National Forest managed Newberry National Volcanic Monument.

Ecosystems

Lava River Cave’s entrance has two ecosystems. The first is a large plant community of ponderosa pine and bitterbrush. This community is characterized by a warm, dry climate. Summers are warm and sunny while winters are cold and relatively dry. Ponderosa pine is the largest member of this community with bitterbrush, manzanita and snowbrush making up part of the remainder.

The other community is a micro ecosystem (a smaller community within a larger one) caused by the cool air at the cave mouth. When cool cave air mixes with the moist warm air from outside, condensation occurs, providing moist conditions. This provides ideal conditions for plants such as false Solomon’s seal, roses, strawberry, raspberry and wax currant.

Points of Interest

Collapse Corridor (0-1,000’)

The cave’s entrance appears as a large hole in the ground. At the mouth the trail drops suddenly over volcanic rocks bridged by stairs, bringing you to the floor of a large cool chamber where winter-born stalactites and stalagmites of ice persist until the warmer days of June.

The piles of volcanic rock you see in the corridor fell from the roof and sides. Each year the action of ice freezing in the crack pry a few rocks loose. Since most freezing occurs near the entrance, most rocks have fallen here.

Echo Hall (1,000’-1,500’)

Stairs lead upward from the collapsed corridor to the main section of the tunnel. The ceiling of volcanic rock reaches 58 feet above the floor and the cave is 50 feet wide. If you listen, conversations echo in far recesses and voices return in the darkness, giving the hall its unique name.

Notice remnants of the once-molten lava clinging to the tunnel walls. The lava flowed through the tube with varying currents much as a river has currents. In this case, however, the currents left deposits. These appear as slaggy crusts and as rounded overhanging shelves. In other locations, the walls are etched with lateral markings showing the varying levels of the old volcanic flows. Near the end of this hall the 1,500 feet post marks the overhead passage of Highway 97. The highway is 80 feet above the cave floor.

Low Bridge Lane (1,500’-2,000’)

When most of the lava drained out, hot gases were trapped in the interior of the tube. These gases reheated the lining of the cave walls and ceilings, causing the volcanic rock to remelt. This remelting formed a peculiarly shiny, glazed form of lava resembling slumped gray toffee coating the tube walls.

In other areas of the tube volcanic stalactites occur. These “lavacicles” are found in two forms: hollow cylindrically shaped “straws,” formed by escaping gases, and the cone-shaped drip pendants, formed by remelted lava dripping from ceilings and walls.

The ceiling in this area dips to approximately 5.5 feet.

Two Tube Tunnel (2,000’-2,500’)

Where the tube begins to narrow, lava shelves extend across the width of the tunnel. Here two tubes are found for 95 feet with intermittent connecting passages. The lava flowed in both tubes. As the lava fell, the flow surface again roofed over, forming a second smaller tube within the larger main tube, a cave inside a cave!

Sand Gardens (3,200’)

Sand covers part of the cave floor. Where did it come from? Years ago people thought an ancient river flowed through the cave, this the name Lava River Cave. Actually water did carry sand into the cave; but drop by drop, not as a river. Rain and melting snow carried volcanic ash down through the cracks and openings of the lava flow and dripped from the ceiling.

The constant dripping of water has carved a garden of spires and pinnacles in the sand. Since this cycle probably takes hundreds of years, please help us protect these delicate and fragile gardens for others.

To The End (3,000’-5,200’)

At the end of the cave the amount of sand increases. Approximately 310 feet from the end, sand reaches all the way to the ceiling. In the 1930’s two men dug out this last portion. They were curious about how far the cave went beyond the sand barrier.

The cave is thought to continue on, but how much further is not known. The cave is blocked by a sand plug. The size of the plug cannot be determined.