August 26, 2016
Tornadoes: Can We Stop the Cycle?
by John Doak
Destruction and rebuilding are a predictable cycle. So why don't we just build homes that are more tornado-resistant? We can.
Nearly every severe weather season, families in Oklahoma lose their homes — or even their loved ones — to a devastating tornado. Year in and year out, the insurance industry helps the victims rebuild their homes and their lives.
When insured Oklahomans replace lost homes, their new homes will be constructed according to existing building codes. When the next devastating tornado hits, the cycle repeats itself. But what if we could stop the cycle? While we can’t stop tornadic activity, we can build homes that are more tornado-resistant. The city of Moore, Okla., a community all too familiar with rebuilding, is committed to doing just that. And I believe the entire state should follow its lead.
A Tested Community
Moore experienced three significant tornadoes in less than 15 years, including the May 3, 1999, tornado that killed 44 people and caused an estimated $1 billion in damage. The May 8, 2003, tornado caused $370 million in damage, but there was no loss of life. The May 20, 2013, tornado killed 24 people and injured at least 200 more. There, property damage from the 17-mile long swath included an estimated 1,150 destroyed homes; the economic loss was estimated at $2 billion.
Breaking the Cycle
Less than a week after the 2013 Moore tornado, a team of professors, scientists, civil engineering students and professional engineers conducted a reconnaissance trip to the disaster zone. Their goal was to investigate the tornadic impact on buildings and homes. They discovered homes recently built to higher-quality construction standards sustained less damage than homes built to a lesser standard.
Chris Ramseyer, OU associate professor of civil engineering, later presented the team’s findings to the Moore City Council. Ramseyer recommended the council modify the city’s residential building code to lessen the impact from tornadoes. The changes, Ramseyer said, would make homes significantly stronger while only raising the cost of construction 1-2%. The council voted unanimously to approve the new building code.
The new standards require building techniques that allow homes to withstand winds up to 135 miles per hour, rather than the old standard building requirements of 90 miles per hour. The new code requires roof sheathing, hurricane clips or framing anchors, continuous plywood bracing and wind-resistant garage doors. Engineers say a wind-resistant garage door is important because once it is breached, the rest of the home is extremely vulnerable.
While EF-5 tornadoes inflict the most catastrophic damage with winds up to 200 mph, 95% of tornadoes are rated EF-2 (or 135 mph) and below. Even in Moore in 2013, 88% of the damage was caused by wind speeds rated EF-2 or lower. If those homes had been built according to Moore’s new building code, 1,012 of 1,150 damaged homes would have withstood the destructive forces experienced that day.
It’s Time to Take Action
Since 1989, Oklahoma has experienced 1,575 tornadoes that have resulted in almost $32 billion in insured losses. If we assume 88% of those losses fall within the EF-2 or lower wind speed, the loss then falls to $3.84 billion. As we move forward, I will advocate the adoption of the Moore fortified home construction standard as our state standard for new home construction.
Insurance policies require that replacement construction meets existing code. If Oklahoma law requires fortified construction techniques, then insurance companies must cover those tougher requirements. More importantly, a stronger home would be a source of comfort to those who have been victimized by tornadoes.
For our industry and for our neighbors, it’s a win-win.