Hell's Half Acre Lava Field is a

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

lava plain A lava field, sometimes called a lava bed, is a large, mostly flat area of lava flows. Such features are generally composed of highly fluid basalt lava, and can extend for tens or hundreds of kilometers across the underlying terrain. Morph ...

located on the

Snake River Plain The Snake River cutting through the plain leaves many canyons and Canyon#List of gorges, gorges, such as this one near Twin Falls, Idaho The Snake River Plain is a geology, geologic feature located primarily within the U.S. state of Idaho. ...

Idaho Idaho ( ) is a landlocked U.S. state, state in the Pacific Northwest and Mountain states, Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington (state), ...

in the United States. It is the easternmost of the basaltic lava fields on the Snake River Plain, located about west of

Idaho Falls, Idaho Idaho Falls is the fourth most populous city in Idaho and the county seat of Bonneville County. It is the state's most populous city outside the Boise metropolitan area. As of the 2020 census, the population of Idaho Falls was 64,818.2020 Cen ...

and north of

Pocatello, Idaho Pocatello () is the county seat of and the largest city in Bannock County, Idaho, Bannock County, with a small portion on the Fort Hall Indian Reservation in neighboring Power County, Idaho, Power County, containing the city's airport. It is t ...

. In 1976, the

National Park Service The National Park Service (NPS) is an List of federal agencies in the United States, agency of the Federal government of the United States, United States federal government, within the US Department of the Interior. The service manages all List ...

designated the northwestern portion of the site a

National Natural Landmark The National Natural Landmarks (NNL) Program recognizes and encourages the conservation of outstanding examples of the natural history of the United States. It is the only national natural areas program that identifies and recognizes the best e ...

. In 1986, the Bureau of Land Management recommended that of the site, located just southeast of the National Natural Landmark, to be a wilderness study area.

Description of the site

The Hell's Half Acre lava plain is located in Bingham and Bonneville counties in the state of Idaho. The site is about in size. The area where a former

lava lake Lava lakes are large volumes of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression. The term is used to describe both lava lakes that are wholly or partly molten and those that are solidified (sometim ...

existed is marked by a long by wide depression near the summit of the

lava field A lava field, sometimes called a lava bed, is a large, mostly flat area of lava flows. Such features are generally composed of highly fluid basalt lava, and can extend for tens or hundreds of kilometers across the underlying terrain. Morp ...

.Link and Mink, ''Geology, Hydrogeology, and Environmental Remediation: Idaho National Engineering and Environmental Laboratory, Eastern Snake River Plain, Idaho,'' 2001, p. 117. Ten circular pits and two large

lava tube A lava tube, more rarely called a pyroduct, is a 'roofed conduit through which molten lava travels away from its vent'. If lava in the tube drains out, it will leave an empty cave. Lava tubes are common in low-viscosity volcanic systems. La ...

s are also located near the summit. Two major lava flows, each about long by wide, extend from the main lava field to the south and southwest. These two lava flows surround "Morgans Pasture," a kipuka (or older geologic feature which was not covered by lava). More recently, scientists studying aerial photographs of the site discovered a long eruptive fissure partly buried under lava flows just from the northwest boundary of the lava field. This and other features of the site indicate that the fissure vent itself may be long. The site is fairly accessible.

Interstate 15 Interstate 15 (I-15) is a major Interstate Highway in the Western United States, running through Southern California and the Intermountain West. I-15 begins near the Mexican border in San Diego County and stretches north to Alberta, Ca ...

just crosses the southeast corner of the lava field. Two trails have been marked by U.S. Bureau of Land Management personnel. The shorter, trail is marked by blue flags, and takes about 30 minutes to walk.Fanselow, ''Idaho: Off the Beaten Path,'' 2006, p. 117. The longer, trail is marked by red flags, and takes a full day to walk. The latter trail leads to the central vent. A short trail (about in length) with educational signage along the way may be accessed from the north parking lot near the Hell's Half Acre

rest area A rest area is a public facility located next to a large thoroughfare such as a motorway, Limited-access road, expressway, or highway, at which drivers and passengers can rest, eat, or refuel without exiting onto secondary roads. Other names ...

on I-15.Spilde, "Idaho's Cool Rest Areas," ''Idaho Falls Post Register,'' June 9, 2000. A second trail (about in length) with educational signage may be accessed from the south parking lot. This longer trail has a

gazebo A gazebo is a pavilion structure, sometimes octagonal or Gun turret, turret-shaped, often built in a park, garden, or spacious public area. Some are used on occasions as bandstands. In British English, the word is also used for a tent-like can ...

and scenic overlook at about the midpoint. There is also a handicapped-accessible paved loop with educational signage as well. All trails are closed in winter. Over 100,000 people used the trails in 2007. The Hell's Half Acre lava plain is home to a variety of plant species. Among them are bitterbrush, bluebunch wheatgrass, foothills death camas,

evening primrose ''Oenothera'' is a genus of about 145 species of herbaceous flowering plants native to the Americas. It is the type genus of the family Onagraceae. Common names include evening primrose, suncups, and sundrops. They are not closely related to ...

fern The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...

geranium ''Geranium'' is a genus of 422 species of annual, biennial, and perennial plants that are commonly known as geraniums or cranesbills. They are found throughout the temperate regions of the world and the mountains of the tropics, with the gre ...

s, gray rabbitbrush, Indian paintbrush, needle-and-thread grass,

penstemon ''Penstemon'' , the beardtongues, is a large genus of roughly 280 species of flowering plants native to North America from northern Canada to Central America. It is the largest genus of flowering plants endemic to North America. As well as bein ...

prickly pear cactus ''Opuntia'', commonly called the prickly pear cactus, is a genus of flowering plants in the cactus family Cactaceae, many known for their flavorful fruit and showy flowers. Cacti are native to the Americas, and are well adapted to arid climat ...

sagebrush Sagebrush is the common name of several woody and herbaceous species of plants in the genus ''Artemisia (plant), Artemisia''. The best-known sagebrush is the shrub ''Artemisia tridentata''. Sagebrush is native to the western half of North Amer ...

Utah juniper ''Juniperus osteosperma'' (Utah juniper; syn. ''J. utahensis'') is a shrub or small tree native to the southwestern United States. Description The plant reaches , rarely to 9 m, tall. The shoots are fairly thick compared to most junipers, in ...

, and

wild onion Wild onion can refer to * any uncultivated species in the genus ''Allium'', especially: **'' Allium bisceptrum'' ** ''Allium canadense'' ** ''Allium tricoccum'' ** '' Allium validum'' ** '' Allium vineale'' ** ''Allium ochotense'' * '' Asphodelus te ...

. Wildlife is also abundant. Species commonly found here include

bobcat The bobcat (''Lynx rufus''), also known as the wildcat, bay lynx, or red lynx, is one of the four extant species within the medium-sized wild cat genus '' Lynx''. Native to North America, it ranges from southern Canada through most of the c ...

coyote The coyote (''Canis latrans''), also known as the American jackal, prairie wolf, or brush wolf, is a species of canis, canine native to North America. It is smaller than its close relative, the Wolf, gray wolf, and slightly smaller than the c ...

golden eagle The golden eagle (''Aquila chrysaetos'') is a bird of prey living in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. They are one of the best-known bird of pr ...

mule deer The mule deer (''Odocoileus hemionus'') is a deer indigenous to western North America; it is named for its ears, which are large like those of the mule. Two subspecies of mule deer are grouped into the black-tailed deer. Unlike the related whit ...

, elk,

prairie falcon The prairie falcon (''Falco mexicanus'') is a medium-sized Falconiformes, falcon found in Western North America. A separate species from the peregrine falcon, with which it shares some visual similarities, the prairie falcon is, essentially, an ...

pronghorn The pronghorn (, ) (''Antilocapra americana'') is a species of artiodactyl (even-toed, hoofed) mammal indigenous to interior western and central North America. Though not an antelope, it is known colloquially in North America as the American ante ...

red fox The red fox (''Vulpes vulpes'') is the largest of the true foxes and one of the most widely distributed members of the order Carnivora, being present across the entire Northern Hemisphere including most of North America, Europe and Asia, plus ...

es,

red-tailed hawk The red-tailed hawk (''Buteo jamaicensis'') is a bird of prey that breeds throughout most of North America, from the interior of Alaska and northern Canada to as far south as Panama and the West Indies. It is one of the most common members of ...

s, and

sage grouse Sage-grouse are grouse belonging to the bird genus ''Centrocercus.'' The genus includes two species: the Gunnison grouse (''Centrocercus minimus'') and the greater sage-grouse (''Centrocercus urophasianus''). These birds are distributed throug ...

History of the site

Geologists estimate that the Hell's Acre Lava Field was created about 3250 BC.Wilson, ''Field Guide to Geologic Excursions in Utah and Adjacent Areas of Nevada, Idaho and Wyoming,'' 1992, p. 10. The lava field was created by the Lava Ridge-Hell's Half Acre

fissure vent A fissure vent, also known as a volcanic fissure, eruption fissure or simply a fissure, is a linear volcanic vent through which lava erupts, usually without any explosive activity. The vent is often a few metres wide and may be many kilo ...

, and marks the southern edge of this area of volcanic activity. This fissure vent was created when one or more

magmatic dikes Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...

(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

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

, with the fissure vent extending toward the southeast and the Hell's Half Acre site. The

is a

shield A shield is a piece of personal armour held in the hand, which may or may not be strapped to the wrist or forearm. Shields are used to intercept specific attacks, whether from close-ranged weaponry like spears or long ranged projectiles suc ...

type.

Pit crater A pit crater (also called a subsidence crater or collapse crater) is a depression formed by the sinking or collapse of the surface lying above a void or empty chamber, rather than by the eruption of a volcano or lava vent. Pit craters are found ...

s and

spatter cones Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and s ...

follow this active fissure line. Two non-erupting fissures extend northwest from the shield volcano for about . 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 Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or unde ...

quickly flowed out of the volcanic rift. At least eight lava lobes have been identified by geologists. As

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...

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 Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in great-circle distance, straight-line distance from the northernmost part of Western Can ...

.Hammer, "The Lure of Lavas," ''Idaho Falls Post Register,'' June 1, 2003. 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 Benjamin Louis Eulalie de Bonneville (; April 14, 1796 – June 12, 1878) was an American officer in the United States Army, fur trapper, and explorer in the American West. He is noted for his expeditions to the Oregon Country and the Great Basi ...

, a

French French may refer to: * Something of, from, or related to France ** French language, which originated in France ** French people, a nation and ethnic group ** French cuisine, cooking traditions and practices Arts and media * The French (band), ...

-born

United States Army The United States Army (USA) is the primary Land warfare, land service branch of the United States Department of Defense. It is designated as the Army of the United States in the United States Constitution.Article II, section 2, clause 1 of th ...

officer. Bonneville traveled west in 1832, on a leave of absence from the military. His expedition was financed by the wealthy

fur trade The fur trade is a worldwide industry dealing in the acquisition and sale of animal fur. Since the establishment of a world fur market in the early modern period, furs of boreal ecosystem, boreal, polar and cold temperate mammalian animals h ...

John Jacob Astor John Jacob Astor (born Johann Jakob Astor; July 17, 1763 – March 29, 1848) was a German-born American businessman, merchant, real estate mogul, and investor. Astor made his fortune mainly in a fur trade monopoly, by exporting History of opiu ...

. Bonneville saw the site in 1833. The celebrated writer

Washington Irving Washington Irving (April 3, 1783 – November 28, 1859) was an American short-story writer, essayist, biographer, historian, and diplomat of the early 19th century. He wrote the short stories "Rip Van Winkle" (1819) and "The Legend of Sleepy ...

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 Shelley is a city in Bingham County, Idaho, United States. The population was 4,409 at the 2010 census. Since 1927 Shelley has been home to the "Idaho Annual Spud Day", which is celebrated on the 3rd Saturday of September. It typically featur ...

). 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 A wildfire, forest fire, or a bushfire is an unplanned and uncontrolled fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identified as a ...

burned of the site in 1999. In the fall of 2005,

Michael Curtis Reynolds Michael Curtis Reynolds (born April 6, 1958) is an American who was convicted of terrorism-related crimes after a series of December 2005 online discussions with a US judge posing as a militant. Biography Described as a transient, Reynolds was li ...

was arrested at the Hell's Half Acre rest area after the

Federal Bureau of Investigation The Federal Bureau of Investigation (FBI) is the domestic Intelligence agency, intelligence and Security agency, security service of the United States and Federal law enforcement in the United States, its principal federal law enforcement ag ...

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 A substation is a part of an electrical generation, transmission, and distribution system. Substations transform voltage from high to low, or the reverse, or perform any of several other important functions. Between the generating station an ...

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

References

Bibliography

* Alt, David D. and Hyndman, Donald W. ''Roadside Geology of Idaho.'' Missoula, Mont.: Mountain Press Pub. Co., 1989. * Blevins, Winfred. ''Dictionary of the American West.'' Seattle, Wash.: Sasquatch Books, 2001. * Bureau of Land Management. ''Eastern Idaho Proposed MFP Amendment and Final Environmental Impact Statement, Wilderness. Eastern Idaho Wilderness Study.'' Bureau of Land Management, Idaho Falls District, U.S. Department of the Interior. 1986. * Fanselow, Julie. ''Idaho: Off the Beaten Path.'' Guilford, Conn.: Globe Pequot Press, 2006. * "Fire Burns 500 Acres of Brush Near Arco." ''Idaho Falls Post Register.'' September 7, 1999. * Fisher, Vardis and Holmes, Opal Laurel. ''Gold Rushes and Mining Camps of the Early American West.'' Caldwell, Id.: Caxton Printers, 1979. * Garrison, Greg. "Take a Walk on the Wild Side—Spotting Native Plants." ''Idaho Falls Post Register.'' June 11, 2003. * Gulick, Bill. ''Snake River Country.'' Caldwell, Id.: Caxton Printers, 1978. * Hammer, C.G. "The Lure of Lavas." ''Idaho Falls Post Register.'' June 1, 2003. * Kricher, John C. ''A Field Guide to Rocky Mountain and Southwest Forests.'' Boston: Houghton Mifflin Co., 1998. * Kuntz, Mel A.; Spiker, Elliott C.; Rubin, Meyer; Champion, Duane E.; and Lefebvre, Richard H. "Radiocarbon Studies of Latest Pleistocene and Holocene Lava Flows of the Snake River Plain, Idaho: Data, Lessons, Interpretations." ''Quaternary Research.'' 25:2 (February 1986). * Link, P.K. and Mink, Leland L. ''Geology, Hydrogeology, and Environmental Remediation: Idaho National Engineering and Environmental Laboratory, Eastern Snake River Plain, Idaho.'' Boulder, Colo.: Geological Society of America, 2001. * Lubrano, Alfred. "Web Sleuth Testifies in Terror Trial." ''

Philadelphia Inquirer ''The Philadelphia Inquirer'', often referred to simply as ''The Inquirer'', is a daily newspaper headquartered in Philadelphia, Pennsylvania. Founded on June 1, 1829, ''The Philadelphia Inquirer'' is the third-longest continuously operating da ...

.'' July 10, 2007. * Nielsen, Erik. "Landowner Protesting Utah Power Substation." ''Idaho Falls Post Register.'' July 13, 2006. * Purple, Edwin Ruthven and Owens, Kenneth N. ''Perilous Passage: A Narrative of the Montana Gold Rush, 1862-1863.'' Helena, Mont.: Montana Historical Society Press, 1996. * "Sci-Fi Flick to Start Filming Near Casper." ''Idaho Falls Post Register.'' March 21, 1996. * Spilde, Tony. "Idaho's Cool Rest Areas." ''Idaho Falls Post Register.'' June 9, 2000. * Wilson, James R. ''Field Guide to Geologic Excursions in Utah and Adjacent Areas of Nevada, Idaho and Wyoming.'' Salt Lake City: Utah Geological Survey, 1992.

External links

{{authority control Lava fields Landforms of Bingham County, Idaho Landforms of Bonneville County, Idaho National Natural Landmarks in Idaho Rift volcanoes Volcanic fields of Utah Bureau of Land Management areas in Idaho Protected areas of Bingham County, Idaho Yellowstone hotspot Volcanoes of Idaho