No time to teach naval manoeuvres in flood (9)
I believe the answer is:
avalanche
'flood' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for avalanche that I've seen before include "heavy snowfall" , "Rock-fall" , "Large fall of snow or rocks" , "Big slide of snow or stone" , "This dangerous flow from some peaks" .)