A REPORT into the flash flood which ruined the start of last year’s Bournemouth Air Festival has revealed the extent of the devastation.

Some residents were forced out of their homes for more than six months following the storm last August, in which 40.6mm of rain fell within an hour – an event you would expect to see approximately once in 84 years.

View all our pictures of the flash floods in August

The drama even caught the attention of the Cabinet Office in London, who picked up the incident by monitoring social media and contacted the Environment Agency to find out what was happening.

Following the flood, a special council committee was set up to investigate whether there are any lessons that can be learnt for the future. This reveals that Bournemouth council received an email alert from the Met Office at 6.06am on August 18, which stated there was a 20 per cent probability of rainfall amounts exceeding 50mm in six hours and that event total accumulations of 60mm were possible.

The report states: “It could be argued that this alert was correct but unfortunately a 20 per cent probability covering quite a big geographical area is too low to produce an immediate response.

“In the event there was probably very little that could have been done anyway but a better more targeted warning could have been provided as things became more certain.”

Properties started flooding within 15 minutes of the start of the heavy rainfall at 10.30am. It took just half an hour for problems to hit local roads. Wallisdown Road, Castle Lane and many town centre roads were all either closed, impassable or gridlocked.

In the hour following the start of the storm, Wessex Water received 33 emergency calls, the Fire Brigade 52 calls and Bournemouth council received 800 additional calls.

By March 2012, the council had recorded 270 reported or observed incidents of flooding on that day and believes that at least 157 properties were flooded internally. However, one of these people requested help from the council.

The report makes several recommendations, including carrying out a review of communications, improving the way information is collated, collecting rainfall data and maximising all opportunities to gain funding for flood reduction schemes. The report will go to the environment and transport overview and scrutiny panel next Tuesday.