Hurricane Irma – What we Learned


irma1.pngIt’s been 4 weeks.  Hurricane Irma, and here evil twin sister Maria, and her brother Harvey, were a wakeup call to residents in the southeast, Caribbean and Gulf of Mexico, in some ways, for different reasons.  The fact that they occurred within a couple weeks should create a concern in the event that more populated areas get impacted by combined effects.

With Harvey, the hurricane was primarily a water event.  The rains just kept coming because the storm moved so slowly (and then stopped before moving again).  There is no infrastructure system designed for 60 inches of rain.  Not even close.  Not even 12 inches of rain.  Among Harvey ‘s lessons should be that huge rainfall can, and will occur in the future.  For populated area with low lying buildings and infrastructure, this is catastrophic.  We need to move facilities, businesses and houses out of low lying areas.  Stormwater systems need not only be maintained, but that the volumes of water we design for may need to be rethought.  The damage to buildings was significant – the piles of trash will take months to clean up.  And that was before Irma.

Irma was a huge storm that developed very rapidly.  It reached category 5 quickly and maintained it for a longer time than any storm previously.  The winds were 185 mph.  It was a wind and storm surge event.  It overwhelmed the islands and devastated many of them.  Southeast Florida got very lucky.  Lack of power was an issue, but it was restored relatively quickly.  Trees created most of the problems.  When one looks at lessons from Irma, the first is that we do not design for 185 mph winds with gusts over 200 mph.  We may need to rethink codes in light of this storm.  Second, the size of the storm made the exposure to these winds last for hours.  I was “luckily” note in the area of the eye, but we had winds for nearly 40 hours.  Trees, poles and structures are not designed to be rocked for 40 hours by wind.  It weakens joints, connections, (and tree roots).  The time of exposure vs wind speed may be an area for further investigation.  Codes do not necessarily take time of exposure into account.  Storm surge was significant.  6 ft of water flowed quickly down Brickell Avenue in downtown Miami.  We do not design infrastructure for this.  Clearly these conditions should be a consideration.  The whole state was affected.  Transportation and mail service were disrupted.  Getting electrical parts was a challenge given the needs throughout the region.  Not trimming vegetation around power lines, and planting vegetation over utilities or under power lines, as many municipal landscape ordinances suggest, is a HUGE problem.  In fact most of the issues in southeast Florida were vegetation related!  We can easily fix this, and burying power lines won’t solve any problems unless the trees are removed from the right of way.  Oh, and the piles of debris are still around 4 weeks later, and we hear they may be here past Halloween, and maybe Thanksgiving.  And we clearly need laws that require hospitals, assisted living facilities, nursing homes, group homes, etc. to have backup power systems for air conditioning.  Cost doesn’t matter when you kill helpless people because you lack AC!

Then there was Maria.  Wind rain, storm surge.  But fortunately for Florida, it stayed away.  Unfortunately for Puerto Rico it did not.  And Puerto Rico is a great case study in what can really go wrong.  The island’s power grid was wiped out.  The need to upgrade and maintain power infrastructure is essential.  Water and sewer are related to power.  The island doesn’t have good access to either.  The failure of infrastructure was exposed.  Strom surge created heavy damage.  If you are low, you need to build on stilts like the Keys did.  The aftermath is a logistical problem.  You can’t fly into damaged airports.  You cannot mount recovery crews without access.  Drones were a huge help in finding out routes to get from place to place.  One person suggested that the hurricane pushed Puerto Rico back 20+ years.  And they had already defaulted on loans.  The debris will be there for……???  Who knows?.

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