Forecast saves scores of Bangladeshis this rainy season

For the first time in the country, rain-triggered landslides could successfully be forecast using advanced devices, which saved scores of lives in two hill districts this monsoon.

The devices, named Landslide Early Warning System (LEWS), were set up on four hills in Chittagong and Cox's Bazar.

They measured the rainfall and sent early warnings, giving the government agencies enough time to evacuate around a thousand people living in the danger zones before landslides occurred.

"We so far have set up four devices in two districts. These are programmed to send landslide warning messages to 10 cell phones of different government agency people. We have plans to install more such devices in future," said Dr Md Nehal Uddin, director general of Geological Survey of Bangladesh (GSB).

The GSB with support from the Norwegian Geotechnical Institute (NGI) has set up the four LEWS stations -- two in Chittagong city, one in Cox's Bazar Sadar and one in Teknaf. The locations were chosen for their history of being landslide-prone areas.

Before installing the devices, the GSB conducted a survey, analysing event-based rainfall data to determine the rainfall threshold values for the landslides.

"As per our survey, the rainfall threshold values were determined at 100mm in three hours, 200mm in 24 hours and 350mm in three days," said GSB Director Reshad Md Ekram Ali who looks after the LEWS project.

When the rainfall exceeds the thresholds, the automatic rain gauges immediately send SMS to the mobile phones of government personnel, he said.

"And this worked really well this year. Our warning system sent landslide alerts in Chittagong, Cox's Bazar and Teknaf."

Yet, a total of 20 people died in Chittagong, Bandarban and Cox's Bazar in five landslides this monsoon.

When his attention was drawn to this, Reshad said they did not get any early warning in these cases as there was no LEWS on those hills.

"Then again, sometimes landslides can be triggered by manmade reasons even though it rains less than the thresholds we've set in the devices. If people cut hills and make them very steep, landslides can take place even after a little rainfall," he said.

Deputy Commissioner Md Ali Hossain of Cox's Bazar told this correspondent how successfully the devices worked in his district.

On July 25, he received a landslide alert from the LEWS station set up on the Radar Station Hill.

Though it was heavily raining, the district administration immediately started evacuating people living on the hills' slopes and foot. Volunteers lent a hand.

"And within a few hours, landslide occurred. Four shanties were buried in the landslide that night," said DC Ali Hossain.

However, not all could be saved. Five people died in the landslide.

"But we could have saved them if they had listened to us. Nothing happened to those who moved to safer places. But some people did not believe the warning as it is a new system," he said.

A few hundred thousand people live in danger of landslides in the country's hilly regions. Between 2006 and 2013, more than 200 lives perished in mudslides in Chittagong alone, with 127 people killed in a single incident in 2007.