My friend Jan pointed out why you should always keep a land line: cell phones don't get Reverse 911 warnings. This system is used to alert people within a specific geographic area that they need to evacuate. It calls land lines only, not cell phones. Cell phones are not a reliable indicator of geographic location.
One of the reasons many people affected by the Tea Fire got out with only the clothes on their backs is because many of them didn't have land lines, only cell phones. So their first warning that there was a problem came when they looked out the window and saw the hillside opposite them enveloped in flames.
