Hazards associated with tropical storms

What is a good example of a tropical storm with extreme storm surges?

Hurricane Katrina in the Bahamas and southeastern US states.

What happened due to storm surges in Hurricane Katrina?

• Levees to prevent flooding broke.

• Surges 27ft high.

• Winds pushed the water into the shore.

How severe was hurricane Katrina?

Cat. 3 but storm surge 28ft (one of largest ever recorded).

What can affect severity of storm surges?

• Shape of coastline and the sea depth.

• Climate change causes rising sea levels and more surges.

What storm suffered severe landslides?

Storm Kai-tak in the Philippines and Oceania.

How severe were landslides in storm Kai-tak?

• Rocks were dislodged by intense rainfall.

• This killed at least 26 in the day after.

What is a storm surge?

A surge of high water which sweeps inland from the sea, flooding low-lying areas.

What causes storm surges?

From a combination of intense low atmospheric pressure of the tropical storm together with powerful, driving surface winds.

What are storm surges a major cause of?

Widespread destruction and loss of life.

What can storm surges create as well as loss of life?

They inundate agricultural land with saltwater and debris, pollute freshwater supplies and destroy housing and infrastructure.

What can storm surges enhance?

Coastal erosion, which can lead to undermining of buildings and highways.

What are landslides caused by?

Estimated up to 90% each year caused by heavy rainfall, and many are triggered by tropical storms.

How does intense rainfall create landslides?

It increases pure water pressure and weakens cohesion, triggering slope failure.

What happened regarding landslides in 1998?

Hurricane Mitch, one of North Atlantic’s most powerful tropical storms, triggered multiple landslides, killing 18,000 people in Central America.

What can landslides trigger?

May trigger earthquakes in economically stressed regions.

e.g. 2010 Taiwan earthquake occurred after Typhoon Morakot dumped 300mm of rain in 5 days.