Patrol boats and helicopters conducted a search on Sunday for approximately 48 migrants who went missing after their boat sank near the Spanish island of El Hierro. This incident could potentially be the deadliest in 30 years of crossings from Africa to the Canary Islands.

Nine individuals, including one child, have been confirmed dead following the sinking of their boat in the early hours of Saturday morning, according to emergency and rescue services. Rescuers managed to save 27 out of 84 migrants attempting to reach the Spanish coast on Saturday. Three patrol boats and three helicopters participated in the renewed search on Sunday, as confirmed by a Spanish coastguard spokesman to Reuters.

The migrants were from Mali, Mauritania, and Senegal, according to Spanish authorities. The emergency services received a call from the boat shortly after midnight on Saturday, which was located about four miles east of El Hierro. The boat sank during the rescue operation, they said. Wind and poor visibility significantly complicated the rescue efforts.

"After what happened yesterday and if the forecast for the arrival of migrant boats holds true, then it will be the biggest humanitarian crisis to affect the Canary Islands in 30 years," Candelaria Delgado of the Canary Islands government told reporters on Sunday. Three of the rescued migrants suffered from hypothermia and dehydration, according to rescue services.

The nine deceased migrants will be buried on Monday and Tuesday. As hopes of finding more survivors waned, police set up a morgue on El Hierro, authorities said. Among the dead was a child aged between 12-15, according to the NGO Walking Borders, which assists migrants.

Three other boats reached the Canary Islands during the night, carrying 208 migrants. Calm seas and gentle winds typical of late summer in the Atlantic Ocean off West Africa have led to a renewed surge in migrant crossings, local authorities reported this month. The route from Africa to the islands has seen a 154% increase in migrant crossings this year, with 21,620 migrants crossing in the first seven months, according to data from the European Union's border agency Frontex.

In the approximately 30 years of migrant crossings to the islands, the deadliest shipwreck recorded to date occurred in 2009 off the island of Lanzarote when 25 people died.