The first ten minutes: seal the room and fix the timeline
Everything about finding a house snake gets easier if the search area stays one room, so before you search anything, close the doors and windows of the room the vivarium is in and block the gap under its door with a rolled towel. Then fix the timeline in your head: when was the snake last definitely seen, in a hand, in the enclosure at feeding, on the camera of your memory at lights-out? An escape discovered within the hour is a snake that has travelled metres. One discovered after a weekend away is a house-wide problem and should be approached as such, calmly and in the order below.
Room by room, edges first, warmth always
Search the sealed room completely before opening the next door. Snakes travel against structure, so your eyes follow the skirting board line, and your hands move everything that touches a wall: the vivarium stand first, since more escapees are found under their own enclosure than anywhere else, then behind and inside the sofa, along radiator pipes, in the warm dark behind the fridge, the boiler cupboard, the tangle of cables behind the television. Check inside shoes lined up by the door, in laundry baskets, and in any box that offers a coil-sized darkness. As each room is cleared, close it behind you, so the searched area stays searched and the snake's world shrinks by one room at a time.
Stations for the night shift
A snake that survives the daylight search has found a hiding place good enough to beat you, so change tactics and let its habits work instead. Place two or three warm stations against the walls of the most likely rooms: a hide box with one entrance, gentle warmth supplied safely beside it, and a shallow water dish, because an active snake at night will travel the walls and will investigate warmth and water when it finds them. Check the stations quietly, torch in hand, at intervals through the evening rather than in one noisy sweep. Patience is not a consolation prize here; it is genuinely how most house snakes are recovered, found curled in a station at midnight having done exactly what snakes do.
When you find it, and what happens next
Lift the snake calmly, supporting its body rather than snatching at it, and put it straight into a secure tub before you carry it anywhere; a snake dropped mid-celebration is a snake loose again. Give it a quick look over for dust, fibres or injury, then back into the enclosure, but not before the enclosure has been interrogated. Something let it out: a lid corner, a door left a fraction open, a vent worked loose, a gap you have walked past a hundred times. Find that exit and fix it before the snake goes back in, or you have simply reset the puzzle for an animal that has already solved it once. For any question left over once the snake is secure, put a follow-up question to KinsLe's Kimmy; she answers using the KinsLe Answers library.