Efforts to provide relief to the thousands of Guatemalans injured and displaced by Tropical Storm Agatha have been complicated by a number of factors, including volcanic ash from last week's eruption of Pacaya.

The volcanic ash has compounded transportation and drainage problems in Guatemala City, where over 1 meter of rain from Agatha caused flooding and mudslides over the weekend, killing at least 153 people and forcing some 155,000 people to evacuate. Sixteen people were killed in Honduras, and 12 people in El Salvador.

"People were busy this weekend just trying to push out the water from their homes. The volcanic soot all over the ground has complicated things as well because it can block pipes making it difficult for water to drain," said Anne Bousquet, Guatemalan representative for Catholic Relief Services (CRS).

"It's amazing how much of the black soot has been cleaned up though," she added. "Every citizen seems to be doing his or her part, it's nice to see all the solidarity."

Agatha, which is the first named storm of the 2010 season, also opened up giant sinkholes in Guatemala, which have swallowed up entire buildings and blocked roads. Several bridges and roads were collapsed, making it difficult for relief workers to transport aid.

Residents began returning to their homes on Tuesday due to the lack of emergency food and shelter available to them.

"We've gone several days now without aid from the government and we don't have enough water and food," said one resident, according to Reuters.

Relief network ACT Alliance reported that the impact of Agatha on the most vulnerable has been exacerbated by drought and food insecurity in the region.

Other officials have warned that outbreaks of dengue fever and malaria could occur in the coming days.

Guatemalan President álvaro Colom has appealed for foreign aid, asking the Inter-American Development Bank for a $400 million emergency loan.