Alf, I'm glad to see someone discussing the issue of whether the aircraft should have attempted a landing in those conditions. The photos at the scene showed the runway with a noticeable snow covering - I was taken aback that planes would land on that. Unless the conditions had deteriorated sharply between the last landing and the Delta's, previous flights much have encountered the same dodgy conditions.
How does ATC dedide whether the runway has gone beyond an acceptable limit? Is it down mainly to reports from landing aircraft? And is it a matter of professional pride to downplay a hairy moment rather than admit you were briefly terrified?