Updike was once a New Yorker reporter
The acclaimed author of the Rabbit tetralogy told the BBC how the "horrendous" experience had shocked him deeply.
"To actually be seeing it not a mile away was very moving, disturbing, unsettling," he said.
"It's like the bottom fell out of your own existence somehow."
The author, who is based near Boston, described how his grand-stepdaughter alerted him to what was happening.
'Horror of horrors'
They watched the first plane crash on television before moving outside to see across the water to Manhattan.
He was still watching the scene an hour later when what he called the "horror of horrors" occurred.
"My wife and I were staring at this dumbly and suddenly the whole thing gave a little quiver and disappeared."
"It sank down as if somebody had yanked it."
Updike spent a year in England in the 1950s and travelled extensively in Russia, Eastern Europe and Africa.
He said he thought the events would change the way Americans, himself included, saw travel in general.
"My own life has seen the airplane go from something exotic that was flown by stunt flyers to something that everybody takes."
"I don't think anybody will step into a plane again quite as lightly."
Defiance
He compared the tragedy to London's wartime Blitz in terms of loss of life and "deliberately conduced death".
He explained that in defiance of the terrorism, New Yorkers were anxious to get life back to normal as soon as possible.
Despite these efforts to get life back on course, Updike said feelings of anger and frustration in the US were unavoidable.
"There is now a great deal of anger and indignation but the enemy is ghostly and elusive," he said.
"And were the principal conspirator to be removed I think the same forces that conjured him up would conjure up a successor."
The author is one of America's most financially successful novelists, making $500,000 (£339,445) from the film rights of his book Couples alone.
But he is best known for his Rabbit books, which chart the life of a fictional American from his teens to old age.
As the author of these books Updike is considered an acute observer of contemporary American life.
Asked whether he thought these events would change the way America sees itself he said that remained to be seen.
He did say that he thought that the attack was a "terrible blow" to US self-confidence.
"The freedom we have enjoyed in the states has been unusual in world history and may be becoming more unusual."