NEWS - Mauritius says cyclone alert system could help warn of Tsunamis

BBC NEWS has this report

Mauritius' top meteorologist remembers all too vividly one of the big storms of his childhood, when he spent 18 hours crammed into the solidest room in the house with 20 or 30 other people; they could hear cries outside, but could do nothing to help.
[...]
Mauritius did get some warning of December's tsunami.

Mr Sok Appadu had a phone call from a woman whose brothers were in the Seychelles, telling him about giant waves.

At about the same time, international radio and television channels were starting to broadcast the news of damage in Sri Lanka.

At that point, he started alerting police and coastguards and put out a broadcast warning - fast, but not quite fast enough to help Mauritius' sister island Rodrigues, which was struck first.

But by the time the tsunami reached Mauritius itself an hour later, most of the eastern coastline had been evacuated and there was no loss of life.