The WECC Daily Report shows the following, so it could easily have been a maintenance worker who messed up.
The CMRC reported the following outages for today:
From 0000-2400 the COI may be limited to 4,500 MW north to south due to Northern CA Hydro and Midpoint-Summer Lake line loading. From 0600-0800 the COI is further limited to 2,400 MW north to south and 2,450 MW south to north due to Grizzly-Malin #2 500-kV line outage.
From 0800-2400 it is further limited to 1,600 MW north to south and 2,450 MW south to north due to the Grizzly-Malin #2, Buckley-Marion #1, Ashe-Marion #2, Schultz- Raver #1 and Schultz-Echo Lake #1 500-kV line outages.
From 0000-2400 the PDCI may be limited to 2,084 MW south to north due to CISO Operating Procedure T-116Q.
From 0600-2400 the PDCI is further limited to 2,805 MW north to south and 1,904 MW south to north due to the Grizzly-Malin #2, Buckley-Marion #1, Ashe-Marion #2, Schultz-Raver #1 and Schultz-Echo Lake #1 500-kV line outages.
From 0000-2400 the Path 44 is limited to 1,650 MW north to south due to the TL 23002/23010 contingency which is the availability to drop load limit south of SONGS.
From 0000-2400 the West of River/Path 46 is limited to 10,088 MW east to west due to Eldorado-Lugo 500-kV series capacitor segment #3 at Lugo by-passed. From 0000-1600 it is further limited to 10,058 MW east to west due to the McCullough-Victorville capacitor outage.
From 0700-1500 it is further limited to 8,967 MW east to west due to McCullough- Victorville #1 500-kV line outage.
Other Comments: None Yesterday/Weekend/Holiday Notable Events: None
Hard to believe one line being cut would trigger an outage of this size.
This seems to be just local to DWP, power is coming back on in many areas.... DWP spokeswoman on several TV stations, but really didn't have much detail .