Concentrate on the term "Cable Seeking Backhoe"
When someone forgets to call "Julie" (the cable location service) and commences to dig, cables get cut. We're talking one or more fiber bundles with ~144 strands ranging in bandwidth from DS3 (45Meg) up to OC192 (10Gig) _PER PAIR_ or copper bundles of hundreds of pair (up to six-hundred-something pair).
Getting the crew out, blocking the area off (for safety), pulling the cable into a splice trunk (if they're lucky), splicing the media, then sealing and burying the new case takes time.
As often as not, much of the traffic can be re-routed at the switch, but that takes some (keyboard) time too. There is usualy a hierarchy of "who gets connected first" - usually starting with Hospitals, fire, police, businesses ... bottom of the list: the home user.
Three days down had to have been a big cable cut.
The only non-cable-cut outage that was anywhere near that amount of time was when one of the major LD carriers lost their primary and secondary databases (both corrupted) and took down pretty much their whole (data transport) network.
Call SBC, at the least, you'l get credited back on the outage time (sometimes more).
FWIW
Scott