Southend Thud
Interesting that the Overharssens had to be deployed within 10 minutes of snowfall. That is unheard of in airfield winter planning terms.
as stated any decent anti icing product should take care of up 2 cm's of snow.
By actually deploying snow equipment so early you are not allowing time for the product to work on the falling snow and also you are actually sweeping away the product leaving an untreated runway ! Bit of an own goal
It could also mean
1. the product used is not up to scratch and had gone past its sell by date
2. it was not put down correctly or at the required rate.