Spates, noun plural of spate. Synonyms in the same form.
Slew
slews, lots, plenties, rafts, masses, deals, piles, batches, messes, passels, heaps, flocks, mountains, sights, pots, stacks, wads, mints, pecks, muckles
Upsurge
upsurges, surges, outbursts, rushes
Other
freshets
All synonyms for spate →