In a torrential manner, or to a torrential degree(adverb)
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Use "torrentially" in a sentence
"It’s difficult to imagine now, but Haiti was once deeply forested; but 98 percent of the tree cover is gone, leaving eroded hillsides with gullies down which the rain torrentially washes whatever soil is left."
"She wrote furiously, torrentially, determined to get down on paper every thought and emotion that occurred to her as a movie unspooled—every flash of pleasure, every jab of annoyance, every half-formed insight and doubled-back reflection and blind alley and stray tangent."
"She cried then, torrentially, and he lay down with her."