Super typhoons: the ingredients of a Disaster
What is a super typhoon?
To make sense of what happened in the Philippines, here’s what you need to know about typhoons:
Typhoon or hurricane?
British national weather service Met Office teaches us the difference between a typhoon and a hurricane, where they form and the ingredients needed to form one:
Parts of a typhoon
Whether we call them typhoon, hurricane or cyclone, tropical cyclones have the same structure inside and out.
Exterior of a tropical cyclone
Interior of a tropical cyclone
Typhoons increase in strength as they travel above warm waters. Weather agencies around the world have their own system of measuring typhoon strength. American cable channel The Weather Channel gives us a short definition of typhoon categories and the extent of damage they can do on land:
The US Joint Typhoon Warning Centre (JTWC) in Hawaii uses the term ‘super typhoon’ for tropical cyclones reaching maximum sustained 1-minute surface winds of at least 150mph or 240kph.
The super storm
In this satellite video, Australian weather info site The Weather Chaser shows the formation of super typhoon Megi (Philippine name: Juan, 2010) in the northwest Pacific and follows its trail as it hit the Philippines, Taiwan and China:
When super typhoon Yolanda made landfall on 8 November 2013 at around 5am, local weather unit Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa) recorded wind speeds of 235kph and gustiness of 275kph. Canadian world news agency Global News reviews how super typhoon Yolanda was different from other typhoons:
Because of its strength, many weather experts are saying that super typhoon Yolanda could be a record breaker in the history of storm tracking. Some residents of the most affected areas in the Philippines were able to capture the wrath of the super typhoon as it passed their regions.
The deadly consequence: storm surges
While we usually associate tropical cyclones with rain and wind, another destructive force known as a storm surge can cause severe damage to property and lead to death. The damage brought by storm surges powered by typhoon Yolanda has been likened to a tsunami.
A storm surge is the rise of water due to wind force, creating a wall of water that drowns land and people. Scientific and educational institution National Geographic takes us inside of a hurricane to explain how storm surges are made and why they happen:
Coastal communities are most at risk from storm surges because they are low-lying areas and are close to the sea. This short video simulates how storm surges penetrate inland:
The extent of damage in Tacloban City, Leyte was the consequence of changing sea levels, the geography of the region and the strength of the typhoon. Climate and weather experts from around the world explain the factors that affected the storm surges in this interview by media organisation NPR:
What happened in Tacloban and other devastated areas in the Philippines is not an isolated case. Other powerful typhoons like hurricane Sandy (2012) and hurricane Katrina (2005) in the US and tropical cyclone Bopha (1971) in Bangladesh have also taken lives and brought costly damage to the affected regions.
The American federal weather agency National Oceanic and Atmospheric Administration (NOAA) gives a more in-depth explanation of the causes of storm surge, methods that measure the phenomena and factors that influence the damage caused by storm surges in this Introduction to Storm Surge.