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Mitigating the No. 1 natural disaster in the U.S.

 Here is what insurers need to know about winter flooding.

Hurricane Harvey brought more than 19 trillion gallons of water to Texas, which is enough to cover all of Alaska, California and Texas — the three biggest states in the United States — with one inch of water.

Additionally, Harvey brought at least 20 inches of rain to more than 6 million people. We don’t know how many of them had flood insurance, but when the average cost of a flood policy at about $700 a year, hopefully most were covered.

Harvey is just one example of a devastating flooding situation. Consumers and insurance companies alike should be proactive in mitigating losses from flooding by understanding the risk and types of coverage to protect against it.

Making the wrong assumptions about flood insurance can be costly.

Not all floods are alike.

Many know about the damage that flooding can cause, but might not know about the three main types of flooding, what weather patterns cause floods and how to protect against them.

Floods are the most common natural disaster in the United States. All 50 states have experienced flooding or flash flooding events in the last 5 years. In California alone, there are more than 1,400 dams creating hydro-electric power, providing water storage, and protecting people downstream from riverine flooding — at least, until those dams are overtopped or otherwise overwhelmed by the accumulation of water behind them.

Flooding can result from many catalysts.

The National Severe Storms Laboratory, a division of the National Oceanic and Atmospheric Administration (NOAA), separates floods into three basic types:
– Coastal Flooding: Also called storm surge, this type of flooding is an abnormal rise in water levels in coastal areas, over and above normal tidal changes. It is often caused by strong wind from severe storms.
– Fluvial (Riverine) Flooding: This happens when water levels rise over the top of river or stream banks due to excessive rainfall, snowmelt, ice jams, or a combination of these.
Pluvial Flooding: Also called surface flooding, pluvial flooding occurs when heavy rainfall inundates an area, overwhelming the capacity of the soil to absorb the water or the storm drainage system’s ability to divert the water away.

Winter flooding across the United States can be caused by any one or more of these types of incidents, depending on the local geography and weather patterns. Regardless of the type of flooding, damage can be catastrophic.

Photo: Ben Margot

Wild western weather

Winter rainfall in the Western U.S. creates ample opportunity for winter flooding to occur, as we have seen in the past 12 months. In California, the flooding in the winter of 2017 was nearly unprecedented. In early February of 2017 the operators of the Oroville Dam released at much as 65,000 cubic feet per second down the main spillway, until the spillway began to collapse. That’s nearly 500,000 gallons per second.

Making the wrong assumptions about flood insurance can be costly.

While it is unlikely that winter 2018 will see as much rainfall in California, especially Northern California, the severe wildfires of late summer, early fall 2017 are leaving tens of thousands of acres of hillsides bereft of grass, trees and undergrowth to help stabilize the topsoil. That means that even modest rainfall in the coming winter and spring may well result in damaging mudslides throughout the state.

Insurers need to flag these kinds of issues for consumers who might not be aware of their risk for flood damage.

In the central United States, rainfall is often concentrated in the spring and summer months, associated with massive thunderstorms and tornadoes, but winter flooding is still a genuine concern. NOAA reported that the Mississippi River Valley floods of winter 2016 caused more than $1 billion in damage. For example, the winter 2016 floods damaged or destroyed more than 7,100 structures in St. Louis.

What the public needs to know

FEMA and the National Flood Insurance Program encourage individuals, families and businesses to take a long and realistic look at their potential flood exposure. While we can’t control Mother Nature, we can educate ourselves on the risk and take steps to be prepared.

Preparation must be done from the ground, up… literally. There are a number of flood hazard mitigation techniques that can be employed during the construction of a new building, and many can be retro-fitted into an existing structure. Features such as flood vents on the lowest levels of a building in a known flood hazard area can help to reduce the hydrostatic pressure when water inundates the structure — flood vents give the floodwaters an easy path back out of the lowest level of the building, and water follows the path of least resistance.

There is also a growing trend of utilizing water and mold resistant materials in building design and construction. Wall-board made from Magnesium Oxide rather than gypsum — MgO will not absorb water during a flood event the way that gypsum does; sheathing gypsum wall-boards with a water and mold resistant fiberglass layer in place of the very absorbent paper covering would also help keep water from infiltrating the walls.  Using concrete and tile flooring (there are some amazing tile products on the market now that look exactly like wood floors, and the things that they can do with stamped and stained concrete are remarkable) in lieu of wood, wood laminate, carpet, or other water-vulnerable materials could reduce the damage from a flood immensely.

Coverage counts

Flood insurance can be a powerful tool in the risk management arsenal of any homeowner or business, provided that the insured fully understands the benefits and limitations of their coverage — whether the flood policy is from the NFIP or a private flood insurer.

As with any other sort of disaster plan (house fire, earthquake, tornado, hurricane, etc.), the first step is to understand your exposure to loss, the next step is to formulate a plan to mitigate those exposures.  A licensed and knowledgeable insurance agent can be an invaluable ally in navigating these troubled and turbulent waters. Flood insurance is no panacea, just as with any other insurance policy, flood insurance is one piece of a robust risk management plan.

Source: Michael Brown Property Casualty 360

By | 2017-12-27T21:18:38+00:00 December 27th, 2017|Buildings, Construction, Engineering, GIS, Hydrology, Land Survey, News, Storm Water|