Just found this on the BBC WW2 Peoples' War website (an archive of people's war memories), and thought others might be interested ... It is a series of diary entries by Alfred John Boon, a British soldier stationed in Naples in 1944.
Mar 19th Vesuvius very restless.
Mar 20th Even more so.
Mar 21st Eruption starts. Could see lava erupting from crater. Go up to sites on sides to help evacuation with recovery vehicles. Earth tremors most of the time.
Mar 22nd Tremors during day with loud explosions. Night clouds of smoke with pulsating glows. Showers of ash falling. Continual equipment evacuation.
Mar 23rd Evacuation continues. Canopies on vehicles burnt by ash. Wear balaclavas and helmets night. Great boulders being spewed. Electric storms. Above the crater, lava runs as quick as a stream.
Mar 24th Pity the vineyard owners. Their yards are buried. Help them with their property if possible. Explosions are blowing doors open and causing some structural damage. “Red snow” falling today. Blows in everywhere.
Mar 25th Very little “snow” today. But some rain to churn it up. Material from crater, looks like billowing cauliflowers. Talked to a Volcanologist on mountain. Suggested it was a bit dodgy in their observatory. Said he stay there no matter what. Had waited for it for years.
Mar 26th Very quiet. Dust blowing out to sea. Most equipment moved. Not a lot of damage. Burns mostly to canopies and cables. In Torre Annunziata the dust was a foot deep.
April 1st-4th Visited sites Naples, Salerno, Sorrento. Went to opera Castellammare. Cavalleria Rusticana and Pagliacci.
July 14th Took advance party to Lubico, near Rome. Passed through Cassino. How stupid to smash a place up like that. Didn’t do any good.
July 22nd Went to Scafati. E. and M.E. school, A.O.D. Pontegragnano, Pompeii ruins, and Castlamara, collecting stores and documents. (Not at Pompeii, that was a visit).
There is a great description of the eruption by the British travel writer, Norman Lewis, who was also stationed in Naples (and in charge of approving marriages between British servicemen and local women!), which I don't have to hand. But you can read a bit more about the eruption and the Allied reaction to it in a blog post entitled, 'Where’s a Volcano Monitoring Station When You Need It?'.