The John Lewis store at Nottingham's intu Victoria Centre will be closed on Wednesday after 80,000 litres of water flooded the shop.
The water burst out of a ruptured heating pipe, leaving the store with no power or lighting.
The Met Office has issued yellow 'be aware' weather alerts of rain for the East Midlands between 10am and 9pm on Wednesday and between 10am and 10pm on Thursday.
A Met Office spokesman added: "Scattered heavy, thundery showers are expected to develop yet again on Wednesday and Thursday and will lead to slow-moving downpours.
"As on preceding days, some locations will miss these downpours but please be aware of possible localised flooding and disruption to travel where they do occur."