Hundreds of rescuers searched on Monday for survivors of landslides and flooding that killed at least 44 people along the coast of Brazil’s southern state of Sao Paulo following a huge weekend downpour.

The worst hit was Sao Sebastiao city in the state of São Paulo, where at least 35 were dead. In neighbouring Ubatuba, a seven-year-old girl was killed. The disaster, in an area famous for beaches flanked by mountains, prompted cancellations in many cities of the Carnival festivities, now in full swing elsewhere in the country.

Governor Tarcisio de Freitas told television network Globo that 40 people were missing. Nearly 800 people were homeless and 1,730 people have been displaced, the São Paulo state government said in a statement.

TV footage showed flooded homes with only their roofs visible. Residents used small boats to carry items and people to elevated positions.

Armed forces joined the search and rescue efforts, aggravated by poor access to many areas after landslides blocked the snaking roads in the region’s highlands and floods washed away chunks of pavement in low-lying and oceanfront areas.

“Our rescue teams are not managing to get to several locations. It is a chaotic situation,” Sao Sebastiao Mayor Felipe Augusto said on social media late on Sunday night.

Augusto said about 50 houses collapsed in the city due to the landslides. He posted several videos of destruction and search efforts, including one of a baby being rescued by locals lined up on a flooded street.

Precipitation in Sao Sebastiao had surpassed 600mm (23.6 inches) within 24 hours over the weekend, among the largest such downpours ever in such a short period in Brazil.

Brazil’s President Luiz Inácio Lula da Silva called for people living in the hillside areas to be relocated to safer regions. “Every now and then nature plays a surprise on us, but also many times we defy nature,” Lula said in remarks to reporters in Sao Sebastiao.

De Freitas declared a state of emergency for the hardest-hit cities, including Sao Sebastiao, Ubatuba, Ilhabela and Bertioga, which enables expedited allocation of funds for relief. On Monday, the governor also declared three days of official mourning throughout the state of Sao Paulo.

Heavy rains affected water, electricity and phone services, according to a statement from the state government, which posted on Twitter a video showing 30,000 litres (7,925 gallons) of water being transported to Sao Sebastiao. Hygiene kits, blankets, sleeping bags, mattresses and medical supplies have also been sent.

Minister of Integration and Regional Development Waldez Góes said on Twitter that experts were looking into reconstruction plans. “In the coming days, we will work on the reconstruction of bridges, public buildings, housing units and all the public infrastructure affected,” Góes said.