The Rattlesnake Hills, also known as Rattlesnake Ridge, is a 16-mile (26 km) long

anticline In structural geology, an anticline is a type of Fold (geology), fold that is an arch-like shape and has its oldest Bed (geology), beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex curve, c ...

mountain

ridge A ridge is a long, narrow, elevated geomorphologic landform, structural feature, or a combination of both separated from the surrounding terrain by steep sides. The sides of a ridge slope away from a narrow top, the crest or ridgecrest, wi ...

Yakima County Yakima County is a County (United States), county in the U.S. state of Washington (state), Washington. As of the 2020 United States census, 2020 census, its population was 256,728. The county seat and most populous city is Yakima, Washington, Ya ...

and Benton County in the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its so ...

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

. It should not be confused with the much smaller Rattlesnake Ridge located near the west end of

Ahtanum Ridge Ahtanum Ridge is a long anticline mountain ridge in Yakima County, Washington, Yakima County in the U.S. state of Washington (state), Washington. It is located just south of the city of Yakima, Washington, Yakima, and much of its length is at the ...

just south of

Yakima, Washington Yakima ( or ) is a city in and the county seat of Yakima County, Washington, United States, and the state's 11th most populous city. As of the 2020 census, the city had a total population of 96,968 and a metropolitan population of 256,728. The ...

and west of

Union Gap, Washington Union Gap is a city in Yakima County, Washington, United States. The population was 6,568 at the 2020 census. Union Gap has become the retail hub for the entire Yakima Valley as a result of Valley Mall and other thriving businesses being locat ...

. The highest point in the hills (as well as Benton County) is the Lookout Summit, which surpasses the more well-known Rattlesnake Mountain by approximately . The Rattlesnake Hills are part of the

Yakima Fold Belt The Yakima Fold Belt of south-central Washington, also called the Yakima fold-and-thrust belt, is an area of topographical folds (or wrinkles) raised by tectonic compression. It is a structural-tectonic sub province of the western Columbia Plat ...

of east-tending long ridges formed by the folding of

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

Columbia River basalt flows. The Rattlesnake Hills form the northern edge of the Yakima Valley, running from the vicinity of Benton City to just south of the city of

Yakima Yakima ( or ) is a city in and the county seat of Yakima County, Washington, United States, and the state's 11th most populous city. As of the 2020 census, the city had a total population of 96,968 and a metropolitan population of 256,728. The ...

, where the

Yakima River The Yakima River is a tributary of the Columbia River in south central and eastern Washington state, named for the indigenous Yakama people. Lewis and Clark mention in their journals that the Chin-nâm pam (or the Lower Snake River Chamnapam N ...

cuts through the mountain ridge via

Union Gap Union Gap is a city in Yakima County, Washington, United States. The population was 6,568 at the 2020 census. Union Gap has become the retail hub for the entire Yakima Valley as a result of Valley Mall and other thriving businesses being locat ...

. To the west of the Yakima River the mountain ridge is known as Ahtanum Ridge. North of the Rattlesnake Hills is

Moxee Valley Moxee is a small suburban community southeast of Yakima, Washington. Yakima and Moxee are both north of the Yakama Indian Reservation in Yakima County, Washington, Yakima County, Washington (state), Washington, United States. The population of M ...

and the Black Rock Valley. The hills extend into the

Hanford Site The Hanford Site is a decommissioned nuclear production complex operated by the United States federal government on the Columbia River in Benton County in the U.S. state of Washington. It has also been known as SiteW and the Hanford Nuclear R ...

. A spur on the north side of the ridge nearly connects with the west end of

Yakima Ridge Yakima Ridge is a long anticline mountain ridge in Yakima County and Benton County in the U.S. state of Washington. From its western end just north of the city of Yakima, the ridge runs east-southeast through the Yakima Training Center to its ea ...

. Roza Canal, used for agricultural irrigation, passes under the Rattlesnake Hills through a tunnel. Named high points of the Rattlesnake Hills, according to the USGS, include Elephant Mountain, Zillah Peak, Eagle Peak, High Top, Lookout, and Rattlesnake Mountain. Yakima Fold Belt map

Rattlesnake Hills AVA

The ''Rattlesnake Hills AVA'' is an

American Viticultural Area An American Viticultural Area (AVA) is a designated wine grape-growing region in the United States, providing an official appellation for the mutual benefit of winery, wineries and consumers. Winemakers frequently want their consumers to know abo ...

located in

and

Benton County, Washington Benton County is a County (United States), county in the south-central portion of the U.S. state of Washington (state), Washington. As of the 2020 United States census, 2020 census, its population was 206,873. The county seat is Prosser, Wash ...

Washington state Washington, officially the State of Washington, is a state in the Pacific Northwest region of the United States. It is often referred to as Washington State to distinguish it from the national capital, both named after George Washington ...

. United States

Alcohol and Tobacco Tax and Trade Bureau The Alcohol and Tobacco Tax and Trade Bureau, statutorily named the Tax and Trade Bureau and frequently shortened to TTB, is a bureau of the United States Department of the Treasury, which regulates and collects taxes on trade and imports of alc ...

(TTB) awarded Rattlesnake Hills its appellation status on March 20, 2006, making Rattlesnake Hills Washington's ninth federally recognized American Viticultural Area. The Rattlesnake Hills AVA is entirely contained within the

Yakima Valley AVA Yakima Valley is the first American Viticultural Area (AVA) established in Washington state on April 3, 1983 by the Bureau of Alcohol, Tobacco and Firearms (ATF), Treasury after reviewing the petition submitted by the Yakima Valley Appellation ...

, which is in turn is entirely contained within the larger

Columbia Valley AVA Columbia Valley is an American Viticultural Area, American Viticultural Area (AVA) which lies within the Columbia River Plateau, through much of central and southern Washington (state), Washington state, with a section crossing the state bounda ...

. The hills form the northern boundary of Yakima Valley, and the AVA includes land between the north bank of the Sunnyside Canal and the entirety of the southern slopes of the Rattlesnake Hills between

Outlook Outlook or The Outlook may refer to: Computing * Microsoft Outlook, also referred to as ''the classic Outlook'' an e-mail client and personal information management software product from Microsoft * Outlook for Windows, also referred to as ''the ...

and the Wapato Dam. The AVA is centered on the city of Zillah. With elevations ranging from to , this AVA contains the highest point in the Yakima Valley AVA.

Yakima Fold Belt

The Rattlesnake Ridge is one of the larger "folds" in the

. The Yakima Fold Belt is an area of topographical folds (or wrinkles) raised by tectonic compression. It is a structural-tectonic sub province of the western

Columbia Plateau The Columbia Plateau is an important geology, geologic and geography, geographic region that lies across parts of the U.S. states of Washington (state), Washington, Oregon, and Idaho. It is a wide flood basalt plateau between the Cascade Range a ...

Province resulting from complex and poorly understood regional tectonics. The folds are associated with geological faults whose seismic risk is of particular concern to the nuclear facilities at the

Hanford Nuclear Reservation The Hanford Site is a decommissioned nuclear production complex operated by the United States federal government on the Columbia River in Benton County in the U.S. state of Washington. It has also been known as SiteW and the Hanford Nuclear Re ...

(immediately north of the Rattlesnake Hills) and major dams on the Columbia and Snake Rivers.

2016 wildfire

The Range 12 fire was started on July 31, 2016, in

eastern Washington Eastern Washington is the region of the U.S. state of Washington located east of the Cascade Range. It contains the city of Spokane (the second largest city in the state), the Tri-Cities, the Columbia River and the Grand Coulee Dam, the H ...

, at the

Yakima Training Center The Yakima Training Center (YTC) is a United States Army training center, used for maneuver training, Land Warrior system testing and as a live fire exercise area. It is located in the south central portion of the U.S. state of Washington, boun ...

northeast of

. The city it started closest to was

Moxee, Washington Moxee is a small suburban community southeast of Yakima, Washington. Yakima and Moxee are both north of the Yakama Indian Reservation in Yakima County, Washington, United States. The population of Moxee was 4,326 at the 2020 census. According ...

on July 30, 2016

local time Local time is the time observed in a specific locality. There is no canonical definition. Originally it was mean solar time, but since the introduction of time zones it is generally the time as determined by the time zone in effect, with daylight s ...

. It quickly grew to over to cover parts of

and Benton County. The fire was the third in recent years to affect the area surrounding the

Hanford Reach National Monument The Hanford Reach National Monument is a national monument in the U.S. state of Washington. It was created in 2000, mostly from the former security buffer surrounding the Hanford Nuclear Reservation. The area has been untouched by development o ...

and the

Arid Lands Ecology Reserve The Arid Land Ecology Reserve (ALE) is the largest tract of shrub-steppe ecosystem remaining in the U.S. state of Washington (U.S. state), Washington. It is managed for the U.S. Department of Energy by the Pacific Northwest National Laboratory (w ...

near Rattlesnake Ridge. The fire was eventually contained through the use of

controlled burn A controlled burn or prescribed burn (Rx burn) is the practice of intentionally setting a fire to change the assemblage of vegetation and decaying material in a landscape. The purpose could be for forest management, ecological restoration, ...

s on Rattlesnake Mountain in Benton County due to concerns that the fire was getting too close to the

, which had recently been compared to the

Fukushima nuclear disaster The Fukushima nuclear accident was a major nuclear accident at the Fukushima Daiichi Nuclear Power Plant in Ōkuma, Fukushima, Japan, which began on 11 March 2011. The cause of the accident was the 2011 Tōhoku earthquake and tsunami, which ...

Newsweek magazine ''Newsweek'' is an American weekly news magazine based in New York City. Founded as a weekly print magazine in 1933, it was widely distributed during the 20th century and has had many notable editors-in-chief. It is currently co-owned by Dev ...

2018 Rattlesnake Ridge landslide

As of January 21, 2018, a large but slow

landslide Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslides ...

is occurring in the Rattlesnake Hills, about 3 miles south of

, USA. The event first drew news coverage in late 2017, after a long fissure was discovered high on Rattlesnake Ridge: this fissure was reported to be 250 feet deep in one place. The first road closure for public safety was reported on December 17, 2017. The

Washington State Department of Natural Resources The Washington State Department of Natural Resources (DNR) manages over of forest, rangeland, range, agricultural, and commercial lands in the U.S. state of Washington (state), Washington. The DNR also manages of aquatic areas which include sh ...

has a web-page providing information on the event, which reports that the moving mass of

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 ...

is about 4 million tons, covering about 20 acres, and it is slipping roughly south at a rate of about 1.5 feet per week. On the weekend of January 20–21, 2018 there was flurry of new reporting, which highlighted a developing consensus that the landslide will at some time collapse suddenly, and that is likely to occur within months if not weeks.

References

{{Washington State hills and ridges Ridges of Yakima County, Washington Landforms of Benton County, Washington Ridges of Washington (state)