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Tropical Depression Grace drenching Haiti days after major earthquake

Widespread rain totals of 5 to 10 inches with localized 15-inch amounts are possible, increasing the threat of flooding and mudslides

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August 16, 2021 at 5:21 p.m. EDT
Satellite view of Tropical Depression Grace at midday Monday. (NOAA)

Tropical Depression Grace is deluging Haiti just days after a devastating earthquake leveled scores of buildings and claimed about 1,300 lives. The tremor, registering at magnitude 7.2, struck around 8:30 a.m. Saturday, collapsing apartment buildings and sending residents running through the streets in fear.

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Now, heavy downpours are pivoting onto Hispaniola and overspreading Haiti late Monday, bringing rainfall rates topping two inches per hour and the threat of flooding and mudslides. The National Hurricane Center wrote “torrential” rains were falling over both the Dominican Republic and Haiti in its 5 p.m. advisory Monday.

Aid workers scramble to save Haiti earthquake victims as storm approaches

Search-and-rescue efforts continue in the wake of the earthquake but could be hampered by the adverse meteorological conditions.

There are growing signs that Grace could threaten Mexico, too, barreling westward through the Caribbean and the Gulf of Mexico and intensifying into a potentially more formidable tropical storm or even hurricane.

Short-term forecast for Grace

As of 5 p.m. Monday, Grace had 35 mph winds and was just shy of tropical-storm intensity as it swept westward at 15 mph about 50 miles south of Port Au Prince, Haiti. Deluging downpours were pinwheeling westward over the nation by midafternoon and will continue into Tuesday.

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The strongest winds should remain offshore, but gusts to 35 mph are still possible in areas reeling from Saturday’s quake. Widespread rain totals of 5 to 10 inches with localized 15-inch amounts will be possible. Haiti, a nation known for its widespread deforestation, is especially susceptible to heavy rainfall. With less vegetation to anchor topsoil, mudslides and landslides are routine during heavy rain events.

That may cause additional casualties while also isolating more remote locales, posing complications for dispatching resources to areas in need.

Compounding disaster in Haiti

Saturday’s earthquake occurred in western Haiti along the Massif de la Hotte Mountains. While the quake was stronger than the one that struck in 2010, it was farther from Port-au-Prince, dramatically reducing shaking in the capital. The temblor was a strike-slip quake, meaning two plates moved side to side. That meant there was little to no tsunami threat. Tsunamis occur when the sea floor moves up and down.

The quake appears to have occurred along the southern rim of the Gonâve Microplate. The depth was very shallow, at only about six miles below ground, causing stronger shaking at the surface. The fault is known as the Enriquillo-Plantain Garden Fault. Plates slide past each other at the fault by about 20 millimeters every year, but big “slips” occur during earthquakes. This one occurred farther west than the 2010 event. In some places, the ground moved horizontally by up to eight feet.

The same fault was responsible for the 2010 quake, as well as a 1907 earthquake that brought widespread damage to Kingstown, Jamaica.

Haiti’s long, terrible history of earthquakes and disaster

Numerous aftershocks have occurred, including some stronger than magnitude 5. Strong quakes are likely to occur for months to come. Some strong aftershocks may occur during the height of heavy rainfall associated with Grace, amplifying the landslide risk even more.

Grace’s longer-term forecast

By later Tuesday, Grace will be pulling westward in the Caribbean away from Hispaniola and is forecast to regain tropical-storm strength. Jamaica could experience tropical-storm conditions Tuesday, as could Cuba’s southern coast.

Assuming the center remains south of Cuba, which is increasingly likely, the storm may continue intensifying as it transits warm ocean waters. That could allow it to grow into a hurricane as it approaches the Yucatán Peninsula late Wednesday into Thursday.

“There is an increasing risk of wind and rainfall impacts over the Yucatán Peninsula of Mexico,” the National Hurricane Center wrote.

If that scenario were realized, it would spell an additional round of land interaction for Grace, which would temporarily weaken it. But it could again intensify north of the Bay of Campeche in the southern Gulf of Mexico and make a run for areas just south of the U.S.-Mexico border late week.

Jason Samenow contributed to this report.

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