Hell's Half Acre Lava Field - History of The Site

History of The Site

Geologists estimate that the Hell's Acre Lava Field was created about 3250 BCE. The lava field was created by the Lava Ridge-Hell's Half Acre fissure vent, and marks the southern edge of this area of volcanic activity. This fissure vent was created when one or more magmatic dikes (sheets or tubes of magma cutting across the existing geologic features) found their way to the surface. At the northwestern edge of the lava field is a shield volcano, with the fissure vent extending toward the southeast and the Hell's Half Acre site. Pit craters and spatter cones follow this active fissure line. Two non-erupting fissures extend northwest from the shield volcano for about 2.7 miles (4.3 km). One scientific team hypothesized that the seven lava fields in the vicinity of Hell's Half Acre may belong to as few as two fissure vents.

Hell's Half Acre was created when basaltic pāhoehoe quickly flowed out of the volcanic rift. At least eight lava lobes have been identified by geologists. As magma and volcanic gases drained from underneath the lava field, the field subsided—leaving behinds hummocks, or "hills" of lava (a feature which Hell's Half Acre retains today). There is evidence that lava filled and drained the lava lake numerous times, and that lava repeatedly overflowed the lake.

Lava from the fissure vent tended to flow downhill toward the southeast, covering part of the fissure. Lava tubes extend in a generally southeastern direction under the lava field, and surfaced in the far southeastern corner of the site. There is also evidence that later pāhoehoe lava lobes ran underneath or inside existing lobes, and then broke out.

The current name of the lava field was given to it by fur traders in the early 19th century seeking passage through the rough terrain of the Rocky Mountains. The term "hell's half acre" was a commonly used expression to describe any rough land. One of the first white people to record their visit to Hell's Half Acre was Benjamin Bonneville, a French-born United States Army officer. Bonneville traveled west in 1832, on a leave of absence from the military. His expedition was financed by the wealthy fur trader, John Jacob Astor. Bonneville saw the site in 1833. The celebrated writer Washington Irving used Bonneville's journals to write a book about the expedition, and based on his descriptions wrote about the area this way:

Here occur some of the wild and striking phenomena of this wild and sublime region. The plain is gashed with numerous and dangerous chasms, from four to ten feet wide, and of great depth. Captain Bonneville attempted to sound some of these openings, but without any satisfactory results. A stone dropped into one of them reverberated against the sides for apparently a great depth.

In the late 19th century and early 20th century, the area was the center of logging activity. Red cedar grew abundantly in the lava field, as the plant can grow directly on rock. In 1889, the village of Woodville was founded near the Woodville Bend of the Snake River (near the modern town of Shelley, Idaho). The Woodville settlers harvested large amounts of red cedar for use as lumber and fuel. These practices were significantly cut back in the 1910s and 1920s as coal became more widely available as a fuel, but the harvesting of red cedar from Hell's Half Acre continued until 1942.

A wildfire burned 500 acres (200 ha) of the site in 1999. In the fall of 2005, Michael Curtis Reynolds was arrested at the Hell's Half Acre rest area after the Federal Bureau of Investigation lured him there with the promise of money and arms from a supporter. More recently, in 2006 the utility Utah Power tried to build an electrical substation near the eastern-most part of Hell's Half Acre lava field.

The Lava Trail System ("formerly Hell's Half Acre") provides pedestrian access to the lava field.