Typhoon Mangkhut, a Category 5 storm that ravaged the
Philippines and China earlier this month, got us thinking about just how bad
typhoons and hurricanes may become if the predictions of climate scientists
continue to be proven accurate. We’ve
all seen the claims that a warmer atmosphere and warmer ocean waters will lead
to stronger storms, higher winds, greater storm surge, and more rain and
flooding. Typhoon Mangkhut and Hurricane
Florence seem consistent with those predictions, and Mangkhut may even call
into question whether a new level of storm classification will be appropriate
in the future.
The idea of a future Category
6 storm classification was the subject of a September 14, 2018 on-line article from the U.K.’s Daily Express, published when
Typhoon Mangkhut was bearing down on the Philippines with wind speeds of an
extraordinary 205 miles per hour. That
made Mangkhut a Category 5 by a wide margin, with the second highest wind speed
on record (behind only 2015’s Hurricane Patricia, which had sustained winds of
215 miles per hour).
The existing five storm categories utilize the following sustained
wind speed ranges:
Category 1: 74 to 95 miles per hourCategory 2: 96 to 110 mphCategory 3: 111 to 129 mphCategory 4: 130 to 156 mphCategory 5: 157 mph or higher
At Mangkhut’s 205 miles per hour and Patricia’s 215 miles
per hour, these storms would be “off the chart” if not for the fact that the Category
5 classification has no top end. Under
the current classification system, Categories 1 through 4 each encompass a
range of between 14 and 26 miles per hour (e.g.,
Category 4 spans 26 miles per hour – that is, 130 to 156 mph). However, the unbounded
Category 5 includes storms with sustained winds of 50 or more miles per hour
stronger than the threshold speed.
Should there be a Category 6? Will there be a Category 6 if these
super-charged storms continue to occur?
Perhaps yes, although the U.S. National Hurricane Center’s description
of the destructive force of a Category 5 storm makes it difficult to imagine exactly
what a Category 6 would do that Category 5 storms don’t already have the power
to do. The National Hurricane Center summarizes the property damage and destruction to be expected in a Category
5 hurricane as follows:
. . . Almost complete destruction of all mobile homes will occur, regardless of age or construction. A high percentage of frame homes will be destroyed, with total roof failure and wall collapse. . . . Significant damage to wood roof commercial buildings will occur due to loss of roof sheathing. Complete collapse of many older metal buildings can occur. Most unreinforced masonry walls will fail which can lead to the collapse of the buildings. A high percentage of industrial buildings and low-rise apartment buildings will be destroyed. Nearly all windows will be blown out of high-rise buildings . . . Nearly all trees will be snapped or uprooted and power poles downed. . . Power outages will last for weeks to possibly months. Long-term water shortages will increase human suffering. Most of the area will be uninhabitable for weeks or months.
That comprehensive description would seem to apply to 200+
mile per hour storms as well. Maybe a
Category 6 classification would remove the qualifiers (“most,” “nearly,”
“possibly”) and simply state that a Category 6 storm WILL result in these
levels of destruction.
Whether we continue to classify all storms with sustained
winds in excess of 156 miles per hour as Category 5, or we add a new Category 6
classification for storms exceeding a higher threshold (185 mph?/ 200 mph?),
the insurance implications are the same.
More storms, stronger storms, higher winds, greater flooding – however
you label them, these storms are a major threat to insureds and insurers
worldwide.
Posted by Dan Millea