The Southern Indian Ocean islands of Reunion and Mauritius have been hit by a storm system which has brought torrential rain.

Tropical Cyclone Haliba formed off the east coast of Madagascar before drifting towards Reunion which lies approximately 950km to the southeast.

Mauritius, which is 227km to the northeast of Reunion, escaped relatively lightly as only the outer rainbands of Haliba impacted the island. At Plaisance Mauritius, 176mm was reported between Saturday and Monday.

Reunion, a French overseas department, with a population of 840,000, did not fare as well. Winds from this storm system were not strong enough to cause any significant damage, but it was a different story with regard to the rain.

Over the last three days, more than 400mm of rain has fallen on the island; double the amount that would be seen in a typical March.

To many of us living outside the tropics, 400mm may seem like an incredible amount of rain. Anything in excess of 50mm is an exceptionally wet day, likely to cause flooding, but on Reunion things are very different.

Here slow-moving tropical cyclones combine with the precipitous topography to generate rain intensities which are impossible to imagine.

On January 7 and 8 1966 Tropical Cyclone Denise crossed Reunion, producing a deluge of biblical proportions. 1,825mm fell at Foc Foc. This is a 24 hour world record that stands to this day.

The island also holds the record for the most rainfall in 72 hours, 3,929mm at Commerson’s Crater, when Cyclone Gamede struck in March 2007. This location also holds records for most rainfall for periods between four and 15 days from a cyclone in 1980.

Fortunately, Haliba is continuing to head south and then southeastwards as a weakening system, blowing itself out over the cooler waters of the far south of the Indian Ocean.

Source: Al Jazeera