Sesnon Fire

The Aliso Canyon gas leak (also called Porter Ranch gas leak and Porter Ranch gas blowout) was a massive natural gas leak in the Santa Susana Mountains near Porter Ranch, Los Angeles, California. Discovered on October 23, 2015, gas was escaping from a well within the Aliso Canyon underground storage facility. This second-largest gas storage facility of its kind in the United States belongs to the Southern California Gas Company (SoCal Gas), a subsidiary of Sempra Energy. On January 6, 2016, Governor Jerry Brown issued a state of emergency. On February 11, the gas company reported that it had the leak under control. On February 18, state officials announced that the leak was permanently plugged. An estimated 97,100 tonnes (95,600 long tons; 107,000 short tons) of methane and 7,300 tonnes (7,200 long tons; 8,000 short tons) of ethane were released into the atmosphere. The initial effect of the release increased the estimated 5.3 Gt of methane in the Earth's atmosphere by about 0.002%, diminishing to half that in 6–8 years. It was widely reported to have been the worst single natural gas leak in U.S. history in terms of its environmental impact. By comparison, the entire rest of the South Coast Air Basin combined, with a population of about 18 million people, emits approximately 413,000 tonnes of methane and 23,000 tonnes of ethane annually. The Aliso gas leak's carbon footprint could be larger than the Deepwater Horizon leak in the Gulf of Mexico.

The Aliso Canyon Oil Field (also Aliso Canyon Natural Gas Storage Field, Aliso Canyon Underground Storage Facility) is an oil field and natural gas storage facility in the Santa Susana Mountains in Los Angeles County, California, north of the Porter Ranch neighborhood of the City of Los Angeles. Discovered in 1938 and quickly developed afterward, the field peaked as an oil producer in the 1950s, but has remained active since its discovery. One of its depleted oil and gas producing formations, the Sesnon-Frew zone, was converted into a gas storage reservoir in 1973 by the Southern California Gas Company, the gas utility servicing the southern half of California. This reservoir is the second-largest natural gas storage site in the western United States, with a capacity of over 86 billion cubic feet of natural gas. Currently it is one of four gas storage facilities owned by Southern California Gas, the others being the La Goleta Gas Field west of Santa Barbara, Honor Rancho near Newhall, and Playa del Rey. Oil production on the field continues from 32 active wells as of 2016. The gas storage reservoir is accessed through 115 gas injection wells, along with approximately 38 miles of pipeline internal to the field. Three operators were active on the field: Southern California Gas Company, The Termo Company, and Crimson Resource Management Corp.

Mission Point, better known as "Mission Peak" to locals, is a spur of Oat Mountain in Los Angeles County, Southern California. At 2,771 feet (845 m) high, it is the second highest peak of the Santa Susana Mountains after Oat Mountain.

Santa Clarita Woodlands Park is a 4,000 acre (1,619 hectare) open space preserve located in the northeastern foothills of the Santa Susana Mountains near Santa Clarita, California.

Renaissance Summit (also known simply as Renaissance or Renaissance at Porter Ranch) is a gated housing subdivision in the northwest San Fernando Valley of the city of Los Angeles, at the highest point in the Porter Ranch neighborhood. Its building and opening was championed by major local political figures in the 1980s and 1990s but was also an ongoing source of controversy in the area.

United Airlines Flight 34 was a scheduled flight departing from San Francisco to Los Angeles, California, on December 27, 1936. At 7:36 am (Pacific time), the co-pilot requested the UAL localizer beacon at Burbank be turned on. The company radio requested aircraft position, to which the co-pilot replied, "just a minute." The aircraft crashed at the head of Rice Canyon (near Newhall, California) at 7:38 am, killing all 12 passengers and crew. The probable cause was found to be "...an error on the part of the pilot for attempting to fly through Newhall pass at an altitude lower than the surrounding mountains without first determining by radio the existing weather."

O'Melveny Park is a public park located in the Santa Susana Mountains, in the Granada Hills community of the northern San Fernando Valley, in the northernmost portion of the City of Los Angeles, California.

Porter Ranch is a suburban-type neighborhood of the City of Los Angeles in the northwest portion of the San Fernando Valley.

Oat Mountain is a peak of the Santa Susana Mountains overlooking the San Fernando Valley (near Los Angeles, California) to the south and southeast. Oat Mountain is the highest peak in the Santa Susana Mountains of California. The Los Angeles district of Chatsworth is to the south of the mountain. There are many microwave relay antennas as well as Doppler weather equipment at Oat Mountain. SoCal Gas has several wells in the area as well.

The Santa Susana Mountains are a transverse range of mountains in Southern California, north of the city of Los Angeles, in the United States. The range runs east-west, separating the San Fernando Valley and Simi Valley on its south from the Santa Clara River Valley to the north and the Santa Clarita Valley to the northeast. The Oxnard Plain is to the west of the Santa Susana Mountains.

The Sunshine Canyon Landfill is a large landfill located in the Los Angeles neighborhood of Sylmar, just south of Newhall Pass. The landfill was commissioned in 1958 and serves Los Angeles County.

Porter Ranch town center is a shopping center located in Porter Ranch, CA, USA. It is anchored by Walmart, Ralphs, Burlington & Best Buy. The center has 45 tenants scattered throughout the shopping center and is located next to the Ronald Reagan Freeway.