(CNN) -- At least 130 people have died and dozens are missing after heavy rains triggered flooding and mudslides that buried communities Sunday and left a swath of destruction in El Salvador, officials said Monday.
The death toll was "preliminary," said Raul Murillo, subdirector of the Department of Civil Protection in San Salvador. Another 13,680 people were staying in emergency shelters, he said.
Laura Mata, communications manager for World Vision in El Salvador, said 40 percent of the dead were children.
About 60 people were still missing Monday afternoon, said Carlos Alvarado, communications director for the government's rescue efforts. The most affected departments are San Salvador, La Paz, Cuscatlan, Usulatan and San Vicente. He described the latter as the most heavily affected.
The government's Web site said there were 108 landslides, 209 destroyed buildings and another 1,835 damaged ones. In all, 18 bridges were affected, it said.
Private, government and U.N. donations have all been promised, but the needs exceeded supplies, with high demand for food, construction materials, plastic sheeting, medications and -- with a cold front expected to sweep into the area Tuesday -- clothes, Alvarado said.
Fumigation efforts were slated to begin Tuesday to reduce the chances of disease.
"There's a lot of work to do," he said.
Guatemala, Spain and other countries were helping, Mata said.
At the 139-bed Hospital Santa Gertrudis in San Vicente, 33 patients sought help overnight in the emergency room, mostly for trauma, broken bones and abrasions, said Dr. Ana Luisa Velazquez, the hospital director.
Patients had to be removed from the pediatric unit and women's surgery unit, both of which were built on low-lying ground and were inundated, she said.
Though the hospital had fresh water from its own well, fresh water was in scarce supply in San Vicente, she said.
Mata visited the town Sunday.
"All three access roads were completely wiped off," she told CNN's Jonathan Mann. "You could only get there by one lane. Everywhere -- mud, huge rocks." Electricity was largely out, she said.
In addition to losing their homes, many people have lost their crops, she said.
President Mauricio Funes declared a national emergency and described the loss as incalculable. About 7,000 people lost homes in the disaster Sunday, officials said.
Authorities said the death toll is expected to rise as rescuers scramble to reach regions where roads have been washed away.
In some of the hardest-hit areas, such as the capital, San Salvador, roads are completely gone, Mata said.
"You would never imagine there were road systems there. ... Huge rocks, mud, water everywhere," she said. "People have lost complete families."
Landslides on the side of a volcano swallowed up a village in Verapaz, Mata said.
Residents in affected areas climbed over boulders as rescue crews waded through muddy water, some carrying young children. Homes, trees and electricity poles, and mountains of mud, covered streets.
The heavy rains in the impoverished Central American nation were unrelated to Hurricane Ida, said Saul Ezgardo de la Reyes, a government meteorologist in the Center of Prognostics.
"The rains in Salvador are due to the low pressure system," he said, adding that it was dissipating Monday. "We're waiting for the arrival of fresh air and higher pressure."
On Sunday, 355 millimeters (14 inches) of rain fell near the Saint Vincent Volcano, southeast of the capital, and 196 mm (7.7 inches) fell on the capital itself, he said.
Sunday's inundations were unprecedented, he said. Hurricane Mitch dropped similar quantities in 1998, but those values were tallied in three or four days, he said. "This was in practically four hours."
A low-pressure system out of the Pacific triggered the disaster, said Robbie Berg of the National Hurricane Center in Miami, Florida.