However, it says the death toll is impossible to predict while much of the site remains under water.

Eastern Daily Press: Cley nature reserve and neighbouring road to the beach was flooded during the storm surge. Picture: ALLY McGILVRAYCley nature reserve and neighbouring road to the beach was flooded during the storm surge. Picture: ALLY McGILVRAY (Image: Archant)

One of the country's oldest nature reserves is expecting casualties when staff return to the flood-hit site.

However, it says the death toll is impossible to predict while much of the site remains under water.

Cley Marshes, a bird breeding sanctuary managed by Norfolk Wildlife Trust, was flooded during the storm surge on Friday night.

However, while many of the neighbouring communities along the coast escaped serious damage, the nature reserve confirmed it is preparing for the worst.

Eastern Daily Press: Members of the National Trust visited the area to examine the extent of the damage. Picture: ALLY McGILVRAYMembers of the National Trust visited the area to examine the extent of the damage. Picture: ALLY McGILVRAY (Image: Archant)

In a statement issued this evening (Saturday), a spokesperson for Norfolk Wildlife Trust (NWT) said: 'There is no doubt that there will be wildlife casualties, especially to the plant and invertebrate life on the reserve. It is impossible to say at this stage what the extent of the losses will be.

'Whilst it seems that most places had a lucky escape from the storm surge on January 13, not so at Norfolk Wildlife Trust's Cley Marshes which has incurred serious flooding and remains largely under seawater and inaccessible.

'This means that for a time there will be limited food available for the many species of birds and other wildlife that depend on the habitats for their survival. It is important, therefore, that the seawater is able to escape on the low tides as quickly as possible so that the freshwater habitats can recover.'

The reserve, which attracts thousands of visitors to north Norfolk throughout the year, is currently closed and the public is being advised to stay away until further notice.

Eastern Daily Press: The flooded reserve as seen from Salthouse Heath on Saturday afternoon. The East Bank bird hide is visible. Picture: ANNE CASEYThe flooded reserve as seen from Salthouse Heath on Saturday afternoon. The East Bank bird hide is visible. Picture: ANNE CASEY (Image: : ANNE CASEY)

However, it is hoped to reopen the visitor centre as soon as the Coast Road - which was also flooded between Cley and Salthouse - is cleared.

The statement added: 'NWT staff have been on the scene and report that there is some damage to infrastructure, but consider it is not as severe as due to the flooding which occurred in a similar storm surge in December 2013.'

Although Friday night's floods did not cause as much devastation as the storm surge three years ago, the reserve revealed it expects the frequency of them to increase.

However, staff have praised the Environment Agency and Natural England for their early warning which gave them more time to prepare - without which the damage could have been worse.

Brendan Joyce, CEO of NWT, said: 'Once we can regain access to the site, a clean-up operation will commence and we will be able to better assess the effects on wildlife and damage to fences, paths, hides and other infrastructure.

'We have been here before so we have an inkling of what to expect. Whilst there will be a lot to do to recover the site, I am confident that we will once again bounce back and have Cley and Salthouse in shape again soon for wildlife and visitors. We are also pleased that so much of the rest of the coast has not been affected and that residents and homes alongside us are safe.

'We know that the frequency of flooding incidents such as this are likely to occur more frequently due to climate change and it is just three years since the last such event. But we expect the reserve and its wildlife to recover and recognise that this is something that we will have to manage over time.'

Visitors are being asked to check the Trust's website www.norfolkwildlifetrust.org.uk for further updates.