Santa Anita decision between Noon-12:30p

[The Indomitable DrugS]

This from Crist's recent article ...

In its first 74 years of racing on dirt, Santa Anita canceled four cards due to rain. In three years of synthetics, it has had to cancel racing 17 times.

I realize that 4 times in 74 years means that Santa Anita cancelled a card for rain once every 18.5 years ... but even that number is friggen absurdly high. I'd really like to know more about the circumstances surrounding those four cards.