Probably more than is needed to close stansted... my friend was telling of me the story...
ATC get on the radio to her
" err... you are going to have to go into stack due to snow here on the ground"
Her "ok"...then gets on the PA to the pax "ladies and gentlemen due to a heavy snowfall we are going to be delayed for around 45 mins"
Get to the bottom of the stack, start their approach...break through the cloud cover...no snow... on finals... still no snow.... land no snow.
Apparently Stansted is one of the worst for closing, even after one snow flake.