Shut in
Definition 1 of 4
Pro Tip 1/3Emergency Situations
Used during events that trap people indoors like storms or lockdowns. 
Residents were shut in during the hurricane.
Pro Tip 2/3Not Imprisonment
Being shut in does not always mean the person is locked up by someone else. 
Snow piled against the door, and we were shut in.
Pro Tip 3/3Temporary Confinement
The situation is mostly temporary until the outside conditions improve. 
After the blizzard passed, the shut-in townsfolk could leave their homes.