spate

A (sudden) flood or inundation of water; specifically, a flood in or overflow of a river or other watercourse due to heavy rain or melting snow; (uncountable, archaic) flooding, inundation.

Thys Lepidium that Pliny & Paul [of Aegina] deſcribe⸝ groweth plentuouſly about the water ſyde that rynneth thorow Morpeth in Northumberland⸝ in ſuche places as great heapes of ſtones are caſten together wyth the myght of a great ſpat or flood.

Arous'd by bluſtering vvinds an' ſpotting thovves, / In mony a torrent dovvn the ſnavv-broo rovves; / VVhile craſhing ice, borne on the roaring ſpeat, / Svveeps dams, an' mills, an' brigs, a' to the gate; […]

A sudden heavy downpour of rain.

Doun comes a jaw o' droukin' rain / Upon their honours— / God sends a spate outower the plain, / Or mebbe thun'ers.

A sudden increase or rush of something; a flood, an outburst, an outpouring.

Thy rural loves are nature's ſel; / Nae bombaſt ſpates o' nonſenſe ſwell; / Nae ſnap conceits, but that ſweet ſpell / O' witchin love, […]

Here is a fine spate of work—a day diddled away, and nothing to show for it!

To (suddenly) flood or inundate (a river or other watercourse) with water.

[H]e paused in a reverie of wilderment and wonder when he could not discern the old fishing-places—they were deeply and darkly flooded for many yards on every side of the spated stream.

A few of the very best angling streams in the Highlands are almost perennial in their flow; the Halladale, on the contrary, is subject to spating.

To (suddenly) rain heavily; to pour.