CMOT, your theory is entirely correct.
Civil defence. It's what all those pointless leisure centres built in the 1970s onwards on ring roads in small towns are for as well. There's a book by Peter Hennessy about the governments preparations for nuclear war, and leisure and conferencing centres were a big part of it. Them and Box Tunnel.
That's why then there is a flood/silly amounts of snow and motorways get shut and housing estates evacuated, people get shunted off to leisure centres en masse.
If it came down to a ladies' nude wrestling match, who would win - Sarah, Michelle or Carla? I've got to say Carla, I reckon she'd fight dirty - nails and everything.