A wildfire in the San Gabriel Mountains of Los Angeles county has already charred more than 1,700 acres and threatens to engulf residential communities in the San Gabriel Valley, reports KTLA.

Dubbed the "Colby Fire," the blaze started at around 5:50 a.m. Thursday morning and may have been started by people.

Glendora police arrested and charged three people with recklessly starting a fire. In a televised press conference, authorities named Clifford Eugene Henry, 22, of Glendora, Jonathan Carl Jarrell, 23, of Irwindale and Steven Robert Aguirre, 21, of Los Angeles.

About 1,000 homes have been evacuated in the Glendora and Azusa areas, according to the Los Angeles County Fire Department, and two structures have already been destroyed. Several schools in the areas including Citrus College, canceled classes for the day, reports the Associated Press. Glendora is a city of 50,000 residents, and Azusa has 47,000 residents.

The LA County Department of Public Health issued a warning for residents who smell smoke or see soot and ash to stay indoors and avoid unnecessary outdoor activities. Officials advised residents to avoid using air conditioning units that draw in air from the outdoors or to retreat to a public place like a library or a mall to avoid harmful air. SUBSCRIBE AND FOLLOW Get the top stories emailed every day. Newsletters may offer personalized content or advertisements. Privacy Policy Newsletter Please enter a valid email address Thank you for signing up! You should receive an email to confirm your subscription shortly. There was a problem processing your signup; please try again later Twitter

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The powerful Santa Ana winds, coupled with California's driest recorded year in 2013, are making it more difficult for the firefighters to keep the blaze under control. Currently, 600 firefighters have been deployed to battle the blaze.

This story is developing...

The blaze is located about 25 miles northeast of downtown Los Angeles. The wildfire's close proximity to LA's more densely populated urban areas created startling skylines in places like Beverly Hills and Pasadena, which wire photographers captured in photos.

Smoke from the Colby Fire is seen in Beverly Hills, California on January 16, 2014. (ROBYN BECK/AFP/Getty Images)

Downtown Los Angeles is shrouded in a cloud of smoke from the Colby Fire, January 16, 2014 in Los Angeles, California. (ROBYN BECK/AFP/Getty Images)

A wildfire burns in the hills just north of the San Gabriel Valley community of Glendora, Calif. on Thursday, Jan 16, 2014. (AP Photo/Nick Ut)

A helicopter drops water on a fire burning near homes on Thursday, Jan. 16, 2014, in Azusa, Calif. (AP Photo/Jae C. Hong)

A fast moving wildfire makes it way up a hill towards a house in the hills just north of the San Gabriel Valley community of Glendora, Calif. on Thursday, Jan 16, 2014.

Family members comfort each other as they evacuate their home as firefighters battle a wildfire, Thursday, Jan. 16, 2014, in Azusa, Calif.

A homeowner attempts to water down a tree on his property while a wildfire burns in the hills just north of the San Gabriel Valley community of Glendora, Calif. on Thursday, Jan 16, 2014.