Hail leads to significant accumulations, lasting until temperatures ease (6)
I believe the answer is:
salute
'hail' is the definition.
(I've seen this before)
'leads to significant accumulations lasting until temperatures ease' is the wordplay.
'leads to' says to take the initial letters.
The initial letters of 'significant accumulations lasting until temperatures ease' is 'SALUTE'.
(Other definitions for salute that I've seen before include "Acknowledge (superior)" , "A greeting, often military" , "Bring hand smartly to cap" , "Ceremonial firing of guns" , "Kind of welcome" .)