Forty thousand High Desert customers lost electricity briefly Friday afternoon, according to a Southern California Edison spokeswoman.


The blackout, which started at 3:55 p.m., affected customers in Hesperia, Victorville, Adelanto and Apple Valley.


Power began to be restored four minutes later, and "by 4:09, most of our customers had their service restored," said Southern California Edison spokeswoman Lauren Bartlett.


The blackout's cause is still under investigation.


The blackout is the first major power outage to hit the city since one caused in October by thieves stealing copper power from a regional substation, leading SoCal Edison employees to shut off power as a security precaution.