The phrase "as it poured" is correct and usable in written English.
You can use it to describe an action occurring simultaneously with heavy rain or a similar pouring action.
Example: "The children played outside, laughing and splashing in the puddles as it poured."
Alternatives: "while it rained" or "as the rain fell."
One interesting job they had was helping fill a silo - stamping on the ensilage as it poured in.
As it poured with rain on Thursday, the hopes of Red Rum's supporters had sunk to their lowest ebb.
As it poured down the length of the troughs, Page jumped out of the cab again and ran back to pull some hay from the truck bed.
The flood caused "sheer devastation", according to residents, as it poured from a culvert and down a side street, ripping huge chunks out of the road surface and destroying the road.
The CIA scornfully denies his bragging, just as it poured scorn on the claims of Miles Copeland, father of pop star Stewart Copeland, who also immodestly trumpeted his supposed work for the Agency.
But you wouldn't have caught him waving a baton at the New York Philharmonic as it poured out a treacly, bright-eyed version of "I Want to Hold Your Hand".
Now and then his thumb must find the button on the joystick and jam it down savagely, making the machine shudder "like a frightened horse" as it pours forth its "eight streams of bullets".
Thanks to its broadening scope, SimpleTuition has been hovering right around profitability, Walker told VentureFizz, sinking into the red at times as it pours revenue back into its business, whether in acquisitions or product development.
Before pouring, the drink is set afire so that as it pours, there is a stream of flames that goes back and forth, creating a true theatrical appeal.
It looks like liquid knuckles as it pours down towards the entrance, while its polished mirror surface curves in both directions, conjuring the childhood delight of running through the warped house of mirrors at Luna Park.
It also creates a continuous rustling as it pours over the monk.
