Their appointments came after Nicholas Pooran stepped down from both positions in November following West Indies' early elimination at the T20 World Cup in Australia.
The first assignments for Hope and Powell come next month when West Indies play three ODIs and three T20 games in South Africa.
Hope is a wicket-keeper batter who has played more than 100 ODIs for West Indies. He has previously filled in as vice captain. Allrounder Powell is a limited-overs specialist and has played 55 T20 internationals. He was the T20 vice captain.
West Indies will co-host the T20 World Cup next year with the United States.
