Indonesian rescuers recovered the bodies of at least 17 people who were swept away in flash floods or buried under tons of mud and rocks that hit hilly villages on the country’s main island of Java, officials said Tuesday.

In December, 10 people were killed in flash floods that hit hilly villages on the country’s main island of Java. In the previous month, flash floods and landslides in North Sumatra province killed at least 29 people.

Rescue teams are tirelessly searching for the missing, braving hazardous conditions and unstable terrain, as per officials. Seasonal rain from about October to March frequently causes flooding and landslides in Indonesia.