Definition of "shrouded"

She wakened in sharp panic, bewildered by the grotesquerie of some half-remembered dream in contrast with the harshness of inclement fact, drowsily realising that since she had fallen asleep it had come on to rain smartly out of a shrouded sky.

1914, Louis Joseph Vance, chapter II, in Nobody, New York, N.Y.: George H[enry] Doran Company, published 1915

I suspect that this large and complex military railway system, shrouded in official secrecy for most of its operational life, remains unknown to many people.

2022 January 12, Chris Hegg, “The secret railway in the woods”, in RAIL, number 948, page 34