What makes you think the lines are separate?
Experience. Phone lines, especially major feeders and trunk lines, are buried as often as possible. That's not possible for high tension and major electrical supply lines except in downtown areas where that type of very expensive infrastructure makes financial sense. The 'last mile' electrical cable between the substation and your home may be buried, but the lines to the substation are almost certainly not. Phone lines are easier to fix, don't require major equipment, and don't need to be brought up in a specific order, either.
I live near I-90 and I-405 interchange. Major traffic issues at rush hour will overload the T-Mobile and Sprint connections in our area (ATT seems to have more capacity), the end of the fireworks display or the SeaFair air show will bring them to their virtual knees. When we had the big windstorm a few years ago (2008?) we were without power for 5 days, but never lost land line. Duval didn't have power for two weeks, but had telephone service within a couple of days.