Facebook, Instagram, Tinder TITSUP*: HOW did anyone even find out?

Updated It appears Facebook and its snap-slinging subsidiary Instagram have fallen off the web. Hook-up-finder Tinder is also reportedly having problems.

As of 22.45 Pacific Time on Monday, (06.45 UTC Tuesday) the websites and apps are apparently still suffering a widespread outage, which kicked off about 40 minutes ago.

Facebook bought Instagram for $715m in 2012, and snapped up WhatsApp for $22bn last year. It's hoped the chat app will remain up and running while its sister sites are down, leaving millions unable to use their accounts.

There's no word on why Tinder is down, though. Presumably the FBI will turn up soon to blame North Korea.

"We're aware of an outage affecting Instagram and are working on a fix. Thank you for your patience," said an Instagram spokesman on arch-rival Twitter as El Reg was going to press.

It's possible Facebook et al are facing a distributed denial-of-service attack; millions of people constantly hitting refresh in their web browsers could be exacerbating whatever has knocked the sites offline, though. Lizard Squad appears to be gloating about the downtime, but that could mean anything and nothing.

The downtime comes right as the US East Coast prepares to be hit by an incoming snow storm: we have no idea how they'll cope penned up indoors without being able to swap pics and tales of the cold – nor keep warm with the help of Tinder.

OHMAGOD THE BLIZZARD JUST TOOK DOWN SOCIAL MEDIA THERE IS CANNIBALISM IN THE STREETS ALL UP AND DOWN THE EASTERN SEABOARD.

— anarchival (@anarchival) January 27, 2015

There's always Google+ and MySpace up and running in case anyone's really hard up for online whittering, plus we assume Reddit, Imgur, SnapChat, WhatsApp, Twitter, Ello, erm, OK the world has enough social networks. We'll bring you more as it happens. ®

Updated at 23.11 PT (07.11 UTC)

Don't worry, Brits waking up and Aussies heading home from work, and everyone else addicted to social meeja, Facebook and Instagram are back online again. You can follow more of the "chaos" on #socialmeltdown2015.

It's understood an internal configuration change broke Facebook and Instagram. FB's Andrew Pope said people were unable to access services after the California company's API servers fell over:

Facebook and Instagram experienced a major outage tonight from 22:10 until 23:10 PST. Our engineers identified the cause of the outage and recovered the site quickly. You should now see decreasing error rates while our systems stabilize. We don't expect any other break in service.