Tributes are pouring in for renowned Quebec medical researcher Dr. Éric Dewailly, 59, who was one of two people killed on Réunion Island in the Indian Ocean, when a cliff above them collapsed as they were picnicking at the foot of a waterfall.

Local police told CBC News that six people — all members of the same extended family — were at the foot of Biberon Falls when the collapse occurred.

Emergency vehicles rushed to the scene of a rockslide at Biberon Falls on Réunion Island, east of Madagascar, on the Indian Ocean. (Stephan and Ludovic Laï-Yu/Journal de l'île de La Réunion)

Claude Grocholski, the commander of the Gendarmerie de la Réunion, said a 29-year-old woman identified as the sister of Dewailly's son-in-law and a resident of Réunion Island, was killed along with Dewailly.

Dewailly's wife, Sylvie Dodin Dewailly, 63, was critically injured and is in hospital.

Three others — Dewailly's daughter, her husband and their eight-month-old son — suffered minor injuries.

Waterfall draws tourists

Grocholski added that several people were near the pool at the foot of the waterfall — a major tourist attraction on the island — when the rock face collapsed.

A local newspaper, le Journal de l'île de La Réunion, reported that the rockslide occurred at around 1 p.m. local time, as the family was enjoying a meal at the site.

Dewailly and family members were picnicking at the foot of this waterfall when a cliff collapsed, killing him and his son-in-law's sister. Other family members were injured. (Google Maps)

A local farmer who witnessed the slide alerted authorities.

"There was an injured woman and a baby who I carried out of harm's way," the farmer, identified only as Michael, told a local radio station. He said one man was trapped by the fallen debris, and a second man had a broken leg.

Canada's Foreign Affairs Ministry said it is offering to help local authorities.

"Our thoughts are with the family and friends of the two Canadian victims involved in a tragic accident on Réunion Island. Canadian consular officials are engaging local authorities to gather additional information and stand ready to provide consular assistance," said a statement released by the ministry Tuesday afternoon.

A medical 'pioneer'

Dewailly was a professor of medicine at Laval University and director of the Laval University Medical Centre's Public Health Research Unit. A medical doctor and specialist in human toxicology, Dewailly was internationally recognized for his work in the Canadian Arctic, studying the endocrine-disrupting effects of environmental toxins in the seafood that makes up the traditional Inuit diet.

"`Professor Dewailly was an engaging and passionate man who threw himself completely into everything he undertook," said Laval University rector Denis Brière in a written statement. "He contributed in a concrete and lasting way to people's health, particularly that of northern populations."

"His admirable body of work will survive his premature passing, which has left us deeply saddened."

Gertrude Bourdon, the executive-director of Laval University's teaching hospital, the Centre Hospitalier universitaire de Québec (CHUQ), and CHUQ Research Centre director Serge Rivest echoed those sentiments.

"This news is a major loss and a major shock for us," Rivest told CBC News.

He called Dewailly a "pioneer" and "the founding father of our line of research into population health and best practices — which now includes more than 90 researchers."

"He was a researcher appreciated not only for the exceptional quality of his research, but also for his humanism and dedication to the community."

Dewailly was also the scientific director of the World Health Organization's Collaborative Centre in Environmental Health.

Dodin Dewailly also renowned

Dewailly's wife, Dr. Sylvie Dodin Dewailly, is also a professor of medicine at Laval University, a gynecologist and a leading Canadian researcher in complementary and alternative medicine, nutrition and women's health.

The extent of her injuries is not yet known.

Réunion Island has about 840,000 inhabitants. The French island is east of Madagascar and about 200 kilometres southwest of Mauritius, the nearest island.

To see an interactive map of Réunion Island, click on the map below: