The landslide was triggered by extreme climatic events of prolonged heavy rainfall combined with rapid melting of a winter snowpack.
(The landslide; was triggered; by extreme climatic events of prolonged heavy rainfall) (prolonged heavy rainfall; combined; with rapid melting of a winter snowpack)
The landslide prolonged heavy rainfall
was triggered combined
by extreme climatic events of prolonged heavy rainfall
with rapid melting of a winter snowpack