The SCU (Santa Clara Unit) Lightning Complex fires were

wildfire A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire ...

s that burned in the

Diablo Range The Diablo Range is a mountain range in the California Coast Ranges subdivision of the Pacific Coast Ranges in northern California, United States. It stretches from the eastern San Francisco Bay area at its northern end to the Salinas Valley are ...

in California in August and September 2020 as part of the

2020 California wildfire season The 2020 California wildfire season, part of the 2020 Western United States wildfire season, was a record-setting year of wildfires in California. By the end of the year, 9,917 fires had burned , more than 4% of the state's roughly 100 mil ...

. The fire complex consisted of fires in Santa Clara,

Alameda An alameda is a Avenue (landscape), street or path lined with trees () and may refer to: Places Canada *Alameda, Saskatchewan, town in Saskatchewan **Grant Devine Dam, formerly ''Alameda Dam'', a dam and reservoir in southern Saskatchewan Chile ...

, Contra Costa, San Joaquin,

Merced Merced (; Spanish for "Mercy") is a city in, and the county seat of, Merced County, California, United States, in the San Joaquin Valley. As of the 2020 Census, the city had a population of 86,333, up from 78,958 in 2010. Incorporated on April 1 ...

, and Stanislaus counties. The name is derived from the three-letter designation given to the

California Department of Forestry and Fire Protection The California Department of Forestry and Fire Protection (CAL FIRE) is the fire department of the California Natural Resources Agency in the U.S. state of California. It is responsible for fire protection in various areas under state responsibi ...

(Cal Fire) division responsible for the Santa Clara, Alameda, Contra Costa, and parts of San Joaquin and Stanislaus counties, and the complex consisted of several distinct fires occurring in this region. The complex fire burned a total of from August 16 to October 1, 2020, making it the fourth-largest overall wildfire recorded in California's modern history, surpassed only by the 2018

Mendocino Complex Fire The Mendocino Complex Fire was a large complex of wildfires that burned in northern California for more than three months in 2018. It consisted of two wildfires, the River Fire and Ranch Fire, which burned in Mendocino, Lake, Colusa, and G ...

, the 2021

Dixie Fire The Dixie Fire was an enormous wildfire in Butte, Plumas, Lassen, Shasta, and Tehama Counties, California. It was named after Dixie Road, near where the fire started in Butte County. The fire began in the Feather River Canyon near Cresta Dam ...

, and the 2020

August Complex fire The August Complex was a massive wildfire that burned in the Coast Range of Northern California, in Glenn, Lake, Mendocino, Tehama, Trinity, and Shasta Counties. The complex originated as 38 separate fires started by lightning strikes on ...

. The SCU Complex was one of several fire complexes burning during August and September in California, most notably the LNU, CZU, and

August August is the eighth month of the year in the Julian and Gregorian calendars, and the fifth of seven months to have a length of 31 days. Its zodiac sign is Leo and was originally named ''Sextilis'' in Latin because it was the 6th month in ...

complexes.

Chronology

The fire complex started on August 16, 2020. It consisted of three zones: the Deer Zone in

Contra Costa County ) of the San Francisco Bay , subdivision_type = Country , subdivision_name = United States , subdivision_type1 = State , subdivision_name1 = California , subdivision_type2 ...

; the Canyon Zone in

, Santa Clara and parts of Stanislaus counties; and the Calaveras zone in parts of Stanislaus, San Joaquin and

counties. On August 20, the fires reached

Lick Observatory The Lick Observatory is an astronomical observatory owned and operated by the University of California. It is on the summit of Mount Hamilton, in the Diablo Range just east of San Jose, California, United States. The observatory is managed by th ...

, an astronomical telescopic

observatory An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysical, oceanography and volcanology are examples of disciplines for which observatories have been constructed. His ...

operated by the

University of California The University of California (UC) is a public land-grant research university system in the U.S. state of California. The system is composed of the campuses at Berkeley, Davis, Irvine, Los Angeles, Merced, Riverside, San Diego, San Francisco, ...

, located on Mount Hamilton. One residential building not in use was destroyed, and some other residential buildings were damaged, but the telescope domes themselves did not burn. By August 26, the Deer zone was fully contained, and the other Canyon and Calaveras zones had grown together into a single branch of the fire. On October 1, Cal Fire reported that the entire fire complex had been fully contained.

Fire impacts

Casualties and property damage

The fire complex had destroyed 222 structures, damaged another 26, and injured 6 people. No fatalities were recorded.

Land ecology

A year following the fire the East Bay Regional Park District (EBRPD) and Save Mount Diablo (SMD) monitored the fire impact on the 6,000 acres of the park district lands. Their observation was that the burn was mostly beneficial for the ecology of the region, despite its extent. This was attributed to the fire's moderate to low intensity which spared most of the park trees, rejuvenated vegetation and triggered germination of rare species of fire poppies. The study prompted CalFire officials to consider increasing the use of prescribed burning in Alameda and Contra Costa counties.

References