From Conquering Fear (2009):

Tourist guides at the Dead Sea today will point out the column of salt that was once, thousands of years ago, Mrs. Lot.

Why salt? There were so many other punishments that might have befallen her. I like to think that she turned to salt because salt is a preservative. . . To live preserved in salt is the fate of people who are so bound to the past or so unsure of their ability to cope with the future that they continue to do what they have always done, even when it no longer fits the circumstances in which they live.

- Rabbi Harold S. Kushner