Avalanches come down to mistakes (9)
I believe the answer is:
landslips
'avalanches' is the definition.
The definition and answer can be both related to natural events as well as being plural nouns.
Perhaps they are linked in a way I don't understand?
'come down to mistakes' is the wordplay.
'come' becomes 'land' (landing is a kind of coming).
'down to' means one lot of letters go next to another (joining in a down clue).
'mistakes' becomes 'slips' ('slip' can be a synonym of 'mistake').
'land'+'slips'='LANDSLIPS'
Can you help me to learn more?
(Another definition for landslips that I've seen is " Disasters - naturally".)