WhereIsAtlas · Philippines

What Happened in Tropical Storm Thelma?

A modest storm that sent a flash flood through Ormoc City in 1991, killing more than 5,000 — one of the Philippines' deadliest disasters.

Tropical Storm Thelma (Uring) hit the Philippines in November 1991, triggering catastrophic flash floods in Ormoc City that killed over 5,000 people. It proved that a storm's flooding — not just its wind — can be its most deadly feature.

A storm that wasn't the strongest

Tropical Storm Thelma arrived in the central Philippines in November 1991. By wind strength it was not the most powerful storm of the year — but that is not what made it so deadly.

The wall of water

What made Thelma catastrophic was the rainfall. Torrential rain fell over the hills above Ormoc City on the island of Leyte, and the water, loaded with soil and debris, surged downhill. A flash flood tore through the low-lying city, sweeping away homes and streets with little warning.

The flood killed more than 5,000 people — a staggering toll for a modest tropical storm.

More deadly than its wind

The Thelma disaster is a recurring case study in disaster science. It showed that the flooding driven by extreme rainfall on hillsides can be far more deadly than the winds that define a storm's category. Deforestation and settlement on slopes amplified the risk, and the city's residents had little time to escape.

The legacy

Thelma reshaped how the Philippines approached flood risk and early warning. It is remembered as one of the deadliest storms in the country's history — a reminder that in a tropical archipelago, the water sometimes kills more than the wind, and that the deadliest hazard is often the one that arrives without warning.

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