Agatha (2010)

A small tropical cyclone formed from a broad area of low pressure and a tropical wave in the eastern Pacific and became a tropical depression near 0000 UTC on 29 May 2010 about 155 nautical miles southwest of Tapachula, Mexico. It strengthened to a tropical storm about six hours later, moved northeastward toward Central America, reached its peak intensity the evening of 29 May, made landfall on the Pacific coast of Guatemala that night, and dissipated over western Guatemala on 30 May. The mid-level remnants may have helped briefly form a surface low in the northwestern Caribbean on 31 May.

Agatha made landfall near Champerico, Guatemala at about 2230 UTC on 29 May while at tropical-storm strength. No other tropical-storm-force landfalls were recorded; the surface circulation quickly weakened as the system moved into the Sierra Madre Mountains and fell apart the next day.

The storm’s maximum sustained winds were 40 knots (46 mph) and the minimum central pressure at peak was 1001 mb, corresponding to a minimal tropical storm (not a hurricane). There were no surface reports of sustained tropical-storm-force winds, though La Unión, El Salvador, reported a gust of 43 kt (about 50 mph).

Storm tide observations along El Salvador’s coast were 1–2 feet above normal on 29 May. Heavy rainfall was the primary hazard: Montufar, Guatemala reported 16.78 inches in 24 hours, Mazatenango, Guatemala reported 22.27 inches during 25–30 May, and in El Salvador Ilopango recorded 8.17 inches, La Unión 7.01 inches, Acajutla 5.71 inches, and Santa Ana 5.91 inches.

The heavy rains caused widespread flooding and deadly mudslides across Guatemala, Honduras, and El Salvador. Official counts attributed about 160 deaths in Guatemala, with additional reports listing 18 fatalities in Honduras and 12 in El Salvador, for a total death toll around 190 (some uncertainty remains about direct versus indirect causes). Damage was severe, with estimated total property losses near $1.1 billion US (about $982 million in Guatemala and $112 million in El Salvador); notable damage included a 20-meter-wide sinkhole in Guatemala City that destroyed several buildings.

Notable aspects include the rarity of tropical cyclone landfalls in Guatemala (only one other confirmed eastern Pacific tropical-storm landfall in Guatemala since reliable records began), reasonably early detection of the precursor disturbance in forecasts, but somewhat larger than average short-term forecast errors for track and intensity for this short-lived system.