The stricken mountain region has seen similar catastrophes in recent decades, including one that caused more than 900 deaths. In the years since, Petropolis presented a plan to reduce risks of landslides, but works have been advancing only slowly. The plan, presented in 2017, was based on analysis determining that 18% of the city's territory was at high risk for landslides and flooding.
Local authorities say more than 180 residents who live in at-risk areas are sheltering in schools. More equipment and manpower is expected to help rescue efforts on Thursday.
Brazil's President Jair Bolsonaro expressed solidarity while on a trip to Russia. Petropolis' city hall declared three days of mourning for the tragedy.