Liked a tweet (Twitter)
This seems to be the first official resource with details about the evacuation warning. Sad that none of the local news, fire, or government sources on Twitter have got this sooner.

Event the local Altadena Sheriff’s station had little detail on a phone call. (I’m sure they got swamped.)

Read Bobcat Fire: Arcadia Warns Of Possible Evacuations As Blaze Surpasses 10,000 Acres (LAist)
The Bobcat fire ignited on Sunday and quickly grew to threaten Mount Wilson.
We’ve just gotten an evacuation warning, so I’m searching around a bit to find sources to back up the text that disappeared. So far there’s nothing in the media, and it may take a half an hour or more to find more details.  This is the only recent story online at the moment and there are a few spurious tweets that cover Altadena in the warning, but those are entirely unsourced.

Phone notifications that disappear too quickly in emergencies can be really bad UI.

Bobcat Fire update
I’m just South and slightly West of the Wilson Observatory which is at the top of the mountain just above our house. Fortunately we’re not in any of the preliminary evacuation zones which are all immediately South of the fire. We won’t really need to worry heavily unless it gets closer to the observatory.

View from the Mount Wilson Observatory East towards the burning flames of the Bobcat Fire
View from the Mount Wilson Observatory facing east toward the fire at 9:00 PM on September 7th.
Topological map of the Bobcat fire in the Angeles National Forest
The Bobcat fire coverage as of about 11:30 AM this morning. (Courtesy of the Angeles National Forest)
Read Tall Plume of Smoke Rises From Fire Near Azusa (NBC Los Angeles)
A tall plume of smoking is rising from a brush fire in the Azusa area during an afternoon of triple-digit heat across Southern California. The tower of smoke from Angeles National Forest can be seen from the San Gabriel Valley and beyond. Details about how the 1,800-acre fire started were not immediately available.  The fire was reported near 14300 West…
Report from 7:07 PM tonight. It’s starting to get dark out now, so I’m hoping the fire quells by itself overnight. I can definitely smell the smoke in the air.
Read Bobcat Fire: 1,800-acre blaze rapidly spreading in Angeles National Forest near Azusa; structures threatened by KTLA Digital Staff (KTLA)

A rapidly spreading fire in the Angeles National Forest near the Azusa area is threatening structures on Sunday, officials said.

The Bobcat Fire erupted around 12:20 p.m. and has scorched about 1,800 acres of heavy fuels, according to forest officials. Video from the scene shows smoke rising from the Azusa area.

“Firefighters are experiencing erratic fire behavior,” officials said.

The fast-moving fire had exploded to about 500 acres by 2:40 p.m., doubled in size in just two hours and then grew another 800 acres by 6 p.m. It was 0% contained.

I noticed that the late afternoon sun was coming in an odd orangish-yellow and presumed there was a fire somewhere. I didn’t know it was this close to the house though!