Definition of spates:
(n) :
(countable, figurative) A sudden increase or rush of something; a flood, an outburst, an outpouring.
(n) :
(countable) A sudden heavy downpour of rain.
(n) :
(countable) 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.
(v) :
(transitive) To (suddenly) flood or inundate (a river or other watercourse) with water.
(v) :
(intransitive) To (suddenly) rain heavily; to pour.