VENICE – By the time Venice’s Mose network of flood barriers was activated Wednesday, it was too late to protect the lagoon city from being inundated with water. But what went wrong?

 It all comes down to the weather forecast, which had predicted a lower than expected high tide peak of 122 c.m. above sea level.

 The 78 barriers of the flood defence system are activated for high tide predictions of 130 c.m. above sea level. On Tuesday, though, the waters unexpectedly rose to 138 c.m.

 By the time authorities became aware of the miscalculation, it was too late to protect the 'floating city' including its famous St Mark’s square, where the basilica and shops were inundated.

 The flood barrier, designed to resist a rise of three metres above normal, can be raised within 30 minutes.

 Given the forecast of a series of high tides in the next few days – expected to peak at 140 c.m. Friday morning – the Mose barriers will remain in place for three days.

 cc