An artificially triggered avalanche thunders down a mountain side at the Vallee de la Sionne in Anzere near Sion, February 3, 2015. The full-scale avalanche dynamics test site is providing scientists and engineers of the Swiss Institute of Research of Snow and Avalanches with essential data to understand and model avalanche motion, according to the Institute website. REUTERS/Denis Balibouse (SWITZERLAND - Tags: ENVIRONMENT SOCIETY SCIENCE TECHNOLOGY TPX IMAGES OF THE DAY)

An artificially triggered avalanche thunders down a mountain side at the Vallee de la Sionne in Anzere near Sion, February 3, 2015. The full-scale avalanche dynamics test site is providing scientists and engineers of the Swiss Institute of Research of Snow and Avalanches with essential data to understand and model avalanche motion, according to the Institute website. REUTERS/Denis Balibouse (SWITZERLAND - Tags: ENVIRONMENT SOCIETY SCIENCE TECHNOLOGY TPX IMAGES OF THE DAY)

An artificially triggered avalanche thunders down a mountain side at the Vallee de la Sionne in Anzere near Sion, February 3, 2015. The full-scale avalanche dynamics test site is providing scientists and engineers of the Swiss Institute of Research of Snow and Avalanches with essential data to understand and model avalanche motion, according to the Institute website. REUTERS/Denis Balibouse ( - Tags: ENVIRONMENT SOCIETY SCIENCE TECHNOLOGY)

An helicopter surveys the site where an avalanche was artificially triggered at the Vallee de la Sionne in Anzere near Sion, February 3, 2015. The full-scale avalanche dynamics test site is providing scientists and engineers of the Swiss Institute of Research of Snow and Avalanches with essential data to understand and model avalanche motion, according to the Institute website. REUTERS/Denis Balibouse (SWITZERLAND - Tags: ENVIRONMENT SOCIETY SCIENCE TECHNOLOGY)

An artificially triggered avalanche thunders down a mountain side at the Vallee de la Sionne in Anzere near Sion, February 3, 2015. The full-scale avalanche dynamics test site is providing scientists and engineers of the Swiss Institute of Research of Snow and Avalanches with essential data to understand and model avalanche motion, according to the Institute website. REUTERS/Denis Balibouse (SWITZERLAND - Tags: ENVIRONMENT SOCIETY SCIENCE TECHNOLOGY)

An artificially triggered avalanche thunders down a mountain side at the Vallee de la Sionne in Anzere near Sion, February 3, 2015. The full-scale avalanche dynamics test site is providing scientists and engineers of the Swiss Institute of Research of Snow and Avalanches with essential data to understand and model avalanche motion, according to the Institute website. REUTERS/Denis Balibouse (SWITZERLAND - Tags: ENVIRONMENT SOCIETY SCIENCE TECHNOLOGY TPX IMAGES OF THE DAY)

An artificially triggered avalanche thunders down a mountain side past a 30 meters (98 feet) high pole holding measuring equiptment, at the Vallee de la Sionne in Anzere near Sion, February 3, 2015. The full-scale avalanche dynamics test site is providing scientists and engineers of the Swiss Institute of Research of Snow and Avalanches with essential data to understand and model avalanche motion, according to the Institute website. REUTERS/Denis Balibouse (SWITZERLAND - Tags: ENVIRONMENT SOCIETY SCIENCE TECHNOLOGY)

Scientists set up laser measurement equipment before triggering an avalanche at the Vallee de la Sionne in Anzere near Sion, February 3, 2015. The full-scale avalanche dynamics test site is providing scientists and engineers of the Swiss Institute of Research of Snow and Avalanches with essential data to understand and model avalanche motion, according to the Institute website. REUTERS/Denis Balibouse ( - Tags: ENVIRONMENT SOCIETY SCIENCE TECHNOLOGY)

An avalanche is triggered by explosive at the Vallee de la Sionne in Anzere near Sion, February 3, 2015. The full-scale avalanche dynamics test site is providing scientists and engineers of the Swiss Institute of Research of Snow and Avalanches with essential data to understand and model avalanche motion, according to the Institute website. REUTERS/Denis Balibouse (SWITZERLAND - Tags: ENVIRONMENT SOCIETY SCIENCE TECHNOLOGY)

An artificially triggered avalanche thunders down a mountain side past a 30 meters (98 feet) high pole holding measuring equiptment, at the Vallee de la Sionne in Anzere near Sion, February 3, 2015. The full-scale avalanche dynamics test site is providing scientists and engineers of the Swiss Institute of Research of Snow and Avalanches with essential data to understand and model avalanche motion, according to the Institute website. REUTERS/Denis Balibouse (SWITZERLAND - Tags: ENVIRONMENT SOCIETY SCIENCE TECHNOLOGY)