spate vs upsurge

spate and upsurge both are nouns.

Word	Noun	Adjective	Verb	Adverb
spate	Yes	No	No	No
upsurge	Yes	No	No	No

As nouns, spate and upsurge are synonyms defined as:

Other synonyms of spate include rush, surge.

spate (noun)	upsurge (noun)
the occurrence of a water flow resulting from sudden rain or melting snow	a sudden or abrupt strong increase
a sudden forceful flow	a sudden forceful flow
(often followed by `of') a large number or amount or extent