C4 2018 Logo

Friday, 14 October 2016

Hurricane Matthew: The Record Breaker

Joanne Kennell, Meteorologist, CatIQ

The destruction ensued by Hurricane Matthew and its remnants, not only in Canada, but in Haiti, Cuba, the Bahamas, the Dominican Republic, and the United States, is heartbreaking. Lives were lost and people’s homes and possessions have been damaged or are in complete ruins. Our thoughts and prayers go out to everyone who is suffering because of this record-breaking storm.

Hurricane Matthew (2016-10-Cat-0081) began as a tropical wave the originated off the west coast of Africa and passed south of Cape Verde – a section of islands located 570 kilometers off the coast of Africa and is a region known for spawning long-lived tropical cyclones. What made Matthew such a record breaker was its intensity and endurance (Erdman, 2016). Not only was Matthew the longest lived Category 4-5 Hurricane on the Saffir-Simpson Hurricane Wind Scale in October in the Atlantic Basin, it was also the southernmost Category 5 Hurricane in the Atlantic Basin.

Tropical cyclones and hurricanes require a set of specific ingredients to form, but generally they need:
1)      A pre-existing disturbance such as a tropical wave
2)      Warm sea-surface temperatures of at least 26oC
3)      At least 5 degrees south or 5 degrees south of the equator for the Coriolis Force       to take effect
4)      Lots of moisture in the lower and mid-levels of the atmosphere
5)      Weak vertical wind shear – a change in wind speed and/or direction with height
6)      Atmospheric instability

According to Dr. Philip Klotzbach, a meteorologist at CSU who specializes in Atlantic Basin seasonal hurricane forecasts, Matthew’s perseverance in the Atlantic Basin was due to a relative lack of wind shear and minimal dry air – exactly two of the key ingredients needed for tropical storm formation. But Matthew did not only break a nine-year streak without an Atlantic Basin Category 5 hurricane, it was also categorized as a Category 5 very far south and close to the equator. On September 30th, just before midnight EDT, Matthew transitioned into a Category 5 hurricane with its centre at 13.3 degrees north.

However, what made Matthew such a record breaker, also made it extremely destructive and devastating. Although Matthew was no longer a hurricane as it impacted Canada’s Maritime Provinces, its leftover moisture, which was absorbed into a frontal zone, intensified a low-pressure system that inundated Nova Scotia and Newfoundland with heavy rains and gusty winds. According to Environment Canada, the town of Sydney, Nova Scotia, received 224.8 mm of rainfall and Gander, NL, received up to 124 mm of rain – both of which were one day record-breaking rainfall totals in each city.

Washed out Road in Buchans, Newfoundland 
Photo credit: Tammy @tammyharris96/Twitter

Unfortunately, all of this rain led to significant flooding in Sydney, including flooded homes and businesses, and many roads and bridges were washed out in Newfoundland. States of emergencies were declared in some Nova Scotia and Newfoundland communities, including Sydney, as well as Lewisporte, Little Burnt Bay, and St. Alban, Newfoundland.

Although the cost of this catastrophic event is unknown, it is expected to exceed CatIQ’s Catastrophe (CAT) threshold of $25M (insured industry loss). But how does this event compare to previous, similar incidents in the past?

Looking back to Hurricane Earl (2010), which did not meet the $25M threshold, but rather industry losses were estimated between $10M and $25M, it also originated from the Cape Verde region. In fact, Earl (2010-09-NE-0090) reached a peak intensity of a Category 4 hurricane and even made landfall near Liverpool, Nova Scotia as a Category 1 hurricane (Cangiolosi, 2011).  So why was Earl’s damage not as extensive like with Hurricane Matthew? Earl was a weakening hurricane at the time, and it was relatively fast moving, so there was not enough time to severely flood cities with massive amounts of rain. However, Matthew’s moisture acted as fuel to intensify a very slow-moving often stalled, low-pressure system. This resulted in unprecedented amounts of rain to fall in both Nova Scotia and Newfoundland.

Track of Hurricane Earl (2010)
Photo credit: Anhamirak and Cyclonebiskit/Wikipedia

Finally, let’s take a look at Hurricane Arthur (2014). Arthur (2014-07-Cat-0058) became an extratropical cyclone on July 5th while over the Bay of Fundy (Berg, 2015), which is located just west of Nova Scotia. Arthur continued to travel northeast toward the Gulf of St. Lawrence while producing strong winds and intense rains over Nova Scotia, Prince Edward Island, and New Brunswick. The system then reached eastern Labrador and Newfoundland. Arthur did in fact reach CatIQ’s Catastrophe (CAT) threshold of $25M by causing localized flooding, damaging properties and structures, downing trees, and causing massive power outages. What Arthur and Matthew had in common is the fact that their remnants of moisture were enhanced along a frontal boundary, which allowed for prolonged periods of rain and strong winds.

Downed Tree of Power Lines in Nova Scotia
Photo credit: Ken Stronach @kstronach24/Twitter

Although every catastrophic and notable event is unique, we can sometimes look for patterns in past events to try to determine potential damages of future, similar systems. Will Hurricane Nicole - who is now the longest-lived Atlantic named storm forming this late in the year - impact Canada as intensely as Matthew? No, it won’t. Parts of Atlantic Canada, predominately eastern Newfoundland including the southern Grand Banks, will only see some ocean swells and gale force winds this weekend. Thank goodness.


Berg, Robbie. 2015. Tropical Cyclone Report: Hurricane Arthur. National Hurricane Center. URL: http://www.nhc.noaa.gov/data/tcr/AL012014_Arthur.pdf

Cangialosi, John P. 2011. Tropical Cyclone Report: Hurricane Earl. National Hurricane Center. URL: http://www.nhc.noaa.gov/data/tcr/AL072010_Earl.pdf

Erdman, Jon. 2016. Hurricane Matthew Shatters Record. Weather.com. URL: https://weather.com/storms/hurricane/news/hurricane-matthew-records-notables-2016

No comments:

Post a Comment