The foothills of the San Gabriel Valley are the

foothills Foothills or piedmont are geography, geographically defined as gradual increases in elevation at the base of a mountain range, higher hill range or an highland, upland area. They are a transition zone between plains and low terrain, relief hill ...

and

hill A hill is a landform that extends above the surrounding terrain. It often has a distinct summit, and is usually applied to peaks which are above elevation compared to the relative landmass, though not as prominent as Mountain, mountains. Hills ...

s in the

San Gabriel Valley The San Gabriel Valley (), sometimes referred to by its initials as SGV, is one of the principal valleys of Southern California, with the city of Los Angeles directly bordering it to the west and occupying the vast majority of the southeastern ...

of eastern

Los Angeles County Los Angeles County, officially the County of Los Angeles and sometimes abbreviated as LA County, is the most populous county in the United States, with 9,663,345 residents estimated in 2023. Its population is greater than that of 40 individua ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. They include the foothills of the

San Gabriel Mountains The San Gabriel Mountains () are a mountain range located in Los Angeles and San Bernardino counties, California, United States. The mountain range is part of the Transverse Ranges and lies between the Los Angeles Basin and the Mojave Desert ...

, and independent low

mountain range A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have aris ...

s of hills, in the east

Greater Los Angeles Greater Los Angeles is the most populous metropolitan area in the U.S. state of California, encompassing five counties in Southern California extending from Ventura County in the west to San Bernardino County and Riverside County in the eas ...

region. The landforms are part of the

Transverse Ranges The Transverse Ranges are a group of mountain ranges of Southern California, in the Pacific Coast Ranges physiographic region in North America. The Transverse Ranges begin at the southern end of the California Coast Ranges and lie within Santa Ba ...

System of

Southern California Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural List of regions of California, region that generally comprises the southern portion of the U.S. state of California. Its densely populated coastal reg ...

and

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

Geography

The ranges are roughly parallel the

San Andreas Fault The San Andreas Fault is a continental Fault (geology)#Strike-slip faults, right-lateral strike-slip transform fault that extends roughly through the U.S. state of California. It forms part of the tectonics, tectonic boundary between the Paci ...

to the north over the San Gabriel Mountains' ridgeline. They are generally along the Interstate 210 freeway, giving it the name "Foothill Freeway". The Interstate 210 and State Route 210 freeway covers 86 miles, between Sylmar in the west, through the foothills and San Gabriel and

Pomona Valley The Pomona Valley is located in the Greater Los Angeles Area between the San Gabriel Valley and San Bernardino Valley in Southern California. The valley is approximately east of downtown Los Angeles. History The earliest inhabitants of Pomo ...

s, to Redlands in the east. The Foothill Freeway superseded a highway known as Foothill Boulevard.

Foothills and hill ranges

;The Foothills and Hills in the San Gabriel Valley region include: * Foothills of the

– ''along southern face''. *

Puente Hills The Puente Hills are a chain of hills, one of the lower Transverse Ranges, in an unincorporated area in eastern Los Angeles County, California, Los Angeles County, California, in the United States. The western end of the range is often referred to ...

* San Jose Hills *

San Rafael Hills The San Rafael Hills are a mountain range in Los Angeles County, California. They are one of the lower Transverse Ranges, and are parallel to and below the San Gabriel Mountains, adjacent to the San Gabriel Valley overlooking the Los Angeles Ba ...

* South Hills *

Verdugo Mountains The Verdugo Mountains, also known as the Verdugo Hills or simply The Verdugos, are a small, rugged mountain range of the Transverse Ranges system in Los Angeles County, California. Located just south of the western San Gabriel Mountains, the Verdu ...

Natural environments

The foothills provide greenbelts and contain Open Space Preserves and

Regional park A regional park is an area of land preserved on account of its natural beauty, historic interest, recreational use or other reason, and under the administration of a form of local government. Definition A regional park can be a special park distr ...

s. The undeveloped hill areas are part of California's chaparral and woodlands

ecoregion An ecoregion (ecological region) is an ecological and geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of land or water, and c ...

– with montane chaparral and woodlands and

Oak savanna An oak savanna is a type of savanna (or lightly forested grassland), where oaks (''Quercus ''spp.) are the dominant trees. It is also generally characterized by an understory that is lush with grass and herb-related plants. The terms "oakery" or ...

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

s. Their

chaparral Chaparral ( ) is a shrubland plant plant community, community found primarily in California, southern Oregon, and northern Baja California. It is shaped by a Mediterranean climate (mild wet winters and hot dry summers) and infrequent, high-intens ...

grassland A grassland is an area where the vegetation is dominance (ecology), dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes such as clover, and other Herbaceo ...

, and oak woodland

plant communities A plant community is a collection or Association (ecology), association of plant species within a designated geographical unit, which forms a relatively uniform patch, distinguishable from neighboring patches of different vegetation types. The comp ...

evolved with

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 ...

s, with some species of their native plants dependent on natural fires to regenerate and thrive. Chaparral is California’s most extensive native plant community. It is also one of the State’s most characteristic wilderness types, dominating foothills and mountain slopes. Properly defined, chaparral is a kind of shrub-dominated community of hard-leaved plants shaped by summer drought, mild, wet winters, and fires that naturally occur every 30 to 150 years plus – more frequent fires can lead to habitat loss and conversion to non-native grasslands."Climate, Fire, and Habitat in Southern California." http://ucanr.edu. N.p., n.d. Web. 6 Dec. 2012. Montane forests are generally pine and fir dominated communities that occur at higher elevations in southern California’s mountain areas from 3000 up to 8500 ft. At the lower parts of the range, dominant trees include big-cone Douglas fir and Coulter pine as well as canyon live oak and California bay. On higher slopes, lodgepole, limber, ponderosa, Jeffrey, and sugar pines occur along with white fir, incense cedar, western juniper, and black and canyon oaks. The low elevation species are sensitive to fire, and thus only found on rocky areas where the geology itself is fire-resistant.

Fire danger

The fire danger in the foothills is very high. Almost all of the cities that the hills go through are cities for which CAL FIRE has made recommendations on Very High Fire Hazard Severity Zones.Cities for Which CAL FIRE Has Made Recommendations on Very High Fire Hazard Severity Zones (VHFHSZ)." CAL FIRE. N.p., n.d. Web. 06 Dec. 2012. There have been a number of wild fires in the foothills of the San Gabriel Valley, that is part of the area's natural environment. Global warming has occurred rapidly over the course of the past half-century. In California, less precipitation will occur as snow, meaning that less water is able to be stored in the snow-pack, and that dry summers could see even less water availability. Summertime peak temperatures will increase in many places. Fire "seasons" may become even longer. The declaration of fire season in California is actually a change in preparedness levels for the California Department of Forestry and Fire Protection. When weather patterns in an area of the state become warm and dry, and vegetation (fuels) are at a low moisture content point, Emergency response dispatch levels are typically increased, facilities are staffed 24 hours a day and additional firefighters are hired. When cooling weather, rain and snow are sufficient to reduce the fire threat, CAL FIRE then reduces its preparedness levels by releasing additional firefighters, closing some of the stations, and repositioning aircraft.Frequently Asked Questions." http://www.fire.ca.gov. N.p., n.d. Web. 6 Dec. 2012.

Notes

References

# "Cities for Which CAL FIRE Has Made Recommendations on Very High Fire Hazard Severity Zones (VHFHSZ)." CAL FIRE. N.p., n.d. Web. 06 Dec. 2012. # "Climate, Fire, and Habitat in Southern California." – Sustainable and Fire Safe Landscapes. N.p., n.d. Web. 05 Dec. 2012. # "Frequently Asked Questions." http://www.fire.ca.gov. N.p., n.d. Web. 6 Dec. 2012. # http://geology.campus.ad.csulb.edu. N.p., n.d. Web. 04 Dec. 2012. #"IE Communities at Risk Www.fireinformation.com." IE Communities at Risk Www.fireinformation.com. N.p., n.d. Web. 04 Dec. 2012. #"San Gabriel Valley." ROAD TRIP USA. N.p., n.d. Web. 04 Dec. 2012. {{DEFAULTSORT:Foothills San Gabriel Valley Geography of the San Gabriel Valley Greater Los Angeles San Gabriel Mountains Mountain ranges of Los Angeles County, California San Gabriel Valley

Geography

Foothills and hill ranges

Natural environments

Fire danger

See also

Notes

References