The Destruction of Pompeii by Mount Vesuvius, Re-Created with Computer Animation
openculture.com
openculture.com
The eruption was documented by contemporary historians and is generally accepted as having started on 24 August 79, relying on one version of the text of Pliny's letter. However the archeological excavations of Pompeii suggest that the city was buried about three months later. This is supported by another version of the letter, which gives the date of the eruption as November 23.
Which makes me want to imagine historians 2000 years from now debating whether 9/11 really occurred on 9/11 or closer to 12/11.
Which almost makes me want to go ask on /r/AskHistorians whether there is any record of Pompeii Truthers. I'd be kinda shocked if there wasn't.
EDIT: Forgot to say when this reform happened. 46 BCE, to take effect in 45 BCE.
They would be arguing at what temperature the Roman column melts.
1) Many of the victims were wearing heavy woolen clothes. Hardly what you would expect on a day in late August in Italy. 2) Shops and restaurants have seasonal foods that are typical of late fall and early winter, not late summer. 3) The latest election ads throughout the town were for an election that took place well after late August 4) A coin was found in such a way that it could not possibly have been dropped by later looters. Currently believed that the earliest the coin could have been minted is late September of 79 (she doesn't give much detail about this).
So yes there is quite a bit of debate about when this happened.
What might be a useful reason for that, except academic exercise? Even being able to tell the exact year some 2000 years later would still be a very precise, all things considered.
For all practical purposes I can imagine, knowing the time of eruption rounded to "in the fall of year NNNN" would be more than enough. Maybe there is a genuine need for more precise dating but the need would have to be partially theoretical due to the fact that it's simply pretty damn difficult to tell. Based on the quoted part, we basically have some old stories and notes which themselves suggest something but still leave many doors open and that's all.
But I think that informs the situation a little. The eruption was going on long enough that Plinius could show up, say "pack up your household, let's go", think about how things were going, disseminate orders to wear pillows on everyone's heads to protect from falling rocks, and even take a bath [1].
[0] Well, maybe just his friends, but he was still a historian who mounted a rescue mission.
[1] which was likely because of an asthma attack and thinking the steam would help, but there is some thought it was to also demonstrate coolness under pressure and help prevent a panic in his charges.
[1] https://en.wikipedia.org/wiki/Eruption_of_Mount_Vesuvius_in_...
You'll find 'em in every era...
How else to explain such sudden deaths, even considering there was enough warning of impending catastrophe, and time to escape? Why else stick it out until that final blast of pyroclastic fury?
Key thing to bear in mind is that, back then, very few people would have had an idea of what was happening and how dangerous it was, even less so about the fact that there was an actual need to escape and what was a safe distance... (Consider this: there is a lot of stuff falling from the sky and low visibility because of the dust in the air, would you run outside or seek cover insider?)
Here there is a more accurate and comprehensive description of events: http://www.bbc.co.uk/history/ancient/romans/pompeii_portents...