rain is beating down / pouring down

the rains break after the dry season
a cloudburst

(Suddenly), it started pouring rain...???

Ich würde es so sagen:
There was a (major/massive) downpour.
There was (major/massive) rainshower.

nina, Monsunregen ist anders wie sonstiges Regen, mMn.

More like a downpour/shower/deluge.

massive??

heavy downpour

There was a sudden heavy downpour.
It suddenly started pouring down.

#5: massive downpour is also fine in colloquial English.

... and the floodgates of the sky were opened. The rain fell upon the earth for forty days and forty nights. ...

a monsoon brings heavy rainfall to the area


heavy rainfall (heavy rains) will hit ..... (the area)

heavy rains hit ...... (whatever area) on ....

bucketing