Hurricane Patricia is now the strongest Pacific Ocean hurricane to make landfall in Mexico. What do Patricia’s record wind speeds mean for our safety and the way we build?
A New Precedent, A New Concern
On Friday 23 October 2015, Hurricane Patricia’s 200 mph maximum sustained winds set a new record as the storm approached the west coast of Mexico. The face of a building exposed to wind acts like a sail. The wind pushes against the face of building and the building must resist that force. The larger the building, the greater the force it collects. As wind speeds rise, so do the wind loads on the building.
Architects and engineers around the world design buildings to resist structural loads from wind and other elements of nature – like the weight of snow or rain on a roof. The anticipated loads the building must meet are typically found in the building code. They vary by location. For example, an area may have high wind load requirements but no requirements for resisting seismic loads from earthquakes.
Wind loads in North and Central America have been carefully studied. Mexico, where Patricia made landfall, has significant recent experience with hurricanes in the mid-2000’s with Wilma in 2005, Lane in 2006 and Dean in 2007. Those hurricanes caused significant damage, particularly to the power grid.
None of those storms was as powerful as Patricia. With sustained winds of 200 mpg, Patricia was similar to a very powerful F-3, almost an F-4, tornado (on the Enhanced Fujita Scale). We may build storm shelters to withstand those loads but they’re so rare in coastal areas our building codes don’t require buildings to withstand such significant force.
The Patricia Effect?
With Patricia’s new record as the most powerful Pacific Ocean hurricane to make landfall in Mexico, we’ll have to wait and see if there’s a Patricia Effect on the insurance industry. There may be some alarm that storms are becoming more powerful and more property damage should be expected. This may cause a rise in insurance premiums which would most certainly be passed along to consumers – the people who visit and vacation in coastal areas.
We should also expect a discussion (at the very least) about raising the wind load requirements in (Mexico’s) building codes. Building codes should always be considered a minimum standard – the least that’s acceptable. Having a public discussion about the standards for building helps residents better understand the limits of the buildings in which we live and work. That understanding empowers us to make better decisions about how to protect ourselves and our neighbors.
Local officials (should) know the history of the building codes for the area. They know the required loads to which the buildings and housing stock were designed so they can monitor relatively slow-moving storms like hurricanes and advise securing property and evacuating when the force of the storm is more than the local building stock is designed to withstand.
Although Patricia weakened significantly after making landfall, it was still important to evacuate to a safer area and return only when it’s safe to do so. The cost of repairing or replacing a building and its contents is nothing compared to the loss of life.
As always, please leave questions and comments below – especially if you’ve got any lessons learned or good advice on getting and staying prepared for a disaster. Thanks!