I don't think AIRMEN would be SAILING if there was anything left of the airfield - but that is just my opinion.
I've been through one of those typhoons where an island was "erased" when it took a direct hit (we were NOT on that island but around 100 miles away) there was no trace of the villages, plant life or anything except for bare coral when it was all over.
Well it might be hard to tell from the air if the runway had been undermined or otherwise damaged by being submerged.