It’s on Alton Towers T&C page
Merlin will endeavour to ensure that as many rides and attractions as possible are available for use by guests at the Attraction. However, we reserve the right, without prior notice, to close and change the programme of rides and attractions and/or the Attraction's operating hours. Merlin in its absolute discretion reserves the right to close the whole or any part of the Attraction at any time or to restrict the number of persons having access to the Attraction. The reason for any closure or restriction provided by this condition may include technical or operational reasons, capacity, inclement weather, special events or to ensure the safety and security of guests or if Merlin reasonably considers the circumstances so require. For tickets purchased in advance, if the whole Attraction is closed for any of the reasons set out above, Merlin may offer replacement Tickets for admission to the Attraction on an alternative date in substitution for any other form of redress.