Ari Fleischer was with then-President George W. Bush on Sept. 11, 2001, for an elementary school visit in Sarasota, Fla. Fleischer, Bush’s press secretary, was present when Bush first heard the first tower had been hit, and he was there when Bush, while reading “The Pet Goat” to second-graders, was told in a whisper that the second tower had been struck.

Thirteen years later, Fleischer is recalling on Twitter, almost minute-by-minute, the events of that morning, offering insight into how the White House scrambled to make sense of the attacks as the president and his staff flew around in Air Force One, believing the safest place at that moment was in the skies — even though there were rumors that the president’s plane was a next target. Among his recollections, Fleischer reveals that he took six-pages of handwritten notes on a legal pad that day of everything Bush was saying and doing. He keeps them in a bank vault.

Here’s the first hour or so of Fleischer’s recounting. (He also did a version of this last year, telling Twitter’s media blog he didn’t intend to do it, but “I got started and I just couldn’t stop.”)