Tropical Storm Agatha

Post Landfall 1 | Summary
Posting Date: June 1, 2010, 8:35:00 AM

The start of the 2010 East Pacific hurricane season was marked by a short-lived, but deadly storm that wreaked havoc in Central America over the weekend. Tropical Depression 1-E formed off the coast of Guatemala on Saturday. Benefitting from low wind shear and sea surface temperatures of 30°C, the system briefly strengthened to Tropical Storm Agatha before making landfall near Guatemala’s border with Mexico. Agatha managed to achieve wind speeds of 45 mph—a minimal tropical storm—before being broken up by Guatemala’s mountainous Pacific coast. By early Sunday, it was once again a tropical depression. Despite unimpressive wind speeds, the storm brought more than a foot of rain to Guatemala and parts of Honduras and El Salvador, triggering flooding and mudslides that washed away roads, bridges, homes and businesses. The region’s coastal mountain ranges enhance precipitation. The warm, moist air is forced to rise and as the rising air cools and water vapor condenses, additional clouds form and boost precipitation. In an unfortunate coincidence, the storm coincided with the eruption last week of the Pacaya volcano, southwest of Guatemala’s capital. The mix of mud and ash will undoubtedly make clean-up efforts more challenging. More than 150 people are reported to have been killed by the storm, 123 in Guatemala alone. However, dozens are still reported missing, so this number may rise. Officials in Guatemala are reporting that more than 3,500 homes were damaged. Meanwhile, a sinkhole opened up in Guatemala City, swallowing a three-story building. It has been suggested, though not confirmed, that Agatha’s heavy rainfall triggered the event. On Sunday, Guatemala’s president announced that more than 100,000 people had been evacuated and nearly 30,000 were living in temporary shelters, either because their homes were destroyed or because they were evacuated in the face of flood threat. At least two dams were reported to be under stress over the weekend, though the immediate danger seems now to have diminished. Yesterday, the presidents of both El Salvador and Honduras declared states of emergency. Construction in Guatemala and El Salvador is dominated by unreinforced masonry (URM) construction. While wind speeds of 45 mph would not be expected to cause significant damage to URM buildings, it is quite vulnerable to flooding. Traditional adobe construction—another highly vulnerable construction type—is also fairly common, particularly in more rural areas, which is where the bulk of the damage and deaths occurred. Much of what was damaged in this storm is unlikely to have been insured. Because of the low take-up rates in the region affected by this storm, AIR does not expect significant insured losses.

Post Landfall 1 | Downloads
Posting Date: June 1, 2010, 8:35:00 AM