Extreme weather measurement is becoming more accurate: here’s why, and what it means for insurers
BMS senior meteorologist Andrew Siffert on the challenge of keeping track of changing weather observation techniques.
On 5 October, Typhoon Koinu passed over Orchid Island, a small landmass off the coast of Taiwan, with a reported wind gust of 213 mph. If approved by the World Meteorological Organization, this observation would be among the highest wind gusts ever measured at a surface weather station.
For insurers it’s vital we keep track of how we measure extreme weather events like this one. But a huge challenge to the industry today is how we keep track of changing weather observation techniques, and the technologies that sit behind them.
As the accuracy with which we can record weather observations improves, and our global observation networks become denser, there is a good chance we will see more extreme weather events being recorded.
This is firstly because the world is installing more weather monitoring stations to capture extremes. To take Orchid Island as an example, the Lanyu weather station was established in 1941 – we have no idea what historical typhoons could have produced in terms of wind speeds prior to that date. Today, with the lower cost of weather stations and solar power with cell services, many areas of the world are installing new weather station networks. This will help us better understand regional extreme weather, particularly in regions that have previously had little monitoring coverage, such as Africa.
We must also account for improvements in technology, which are enhancing monitoring accuracy.
Taking hurricanes as an example, observations suggest that storms are more frequently undergoing rapid intensification (an increase in the sustained winds of a cyclone or hurricane of at least 35 mph in a 24-hour period). A commonly used method for estimating rapid intensification is the Dvorak Technique. Unsurprisingly, this technique has evolved significantly since it was first introduced in the 1960s, and today modifications continue to be made to improve its accuracy. We now know that it’s likely that in the past certain storm intensities would have been underestimated by the Dvorak Technique, due to limited information.
Lastly, since aircraft flight frequency has increased over time, we now have more chances to observe rapid intensification periods. Often in the Atlantic Basin a storm can have multiple aircraft observing it at one time. The aircraft measurements themselves have also become more accurate thanks to improved GPS sensors for measuring wind speeds, as well as improved radars both on the planes and on the ground.
Technology, of course, will constantly be changing. In many respects this might just be the beginning, as further developments help us better understand extreme weather events – from new satellites to sensor-equipped aircraft and vehicles. This will provide difficulties for the insurance industry, which already has problems grasping the frequency and severity of severe weather events and how those perils change over time.
In the face of these difficulties in understanding weather observations and how they could change over time, BMS Re is looking at advanced modeling and analytics to help incorporate weather observations and predictive modeling to assess these trends in extreme weather. In one case, BMS Re partnered with a weather sensor provider to better understand hail impacts on solar panels to quantify potential losses and build an insurance product. These efforts lead to opportunities to collaborate with scientists and share data among the insurance industry, governments and the private sector to better understand extreme weather risks.
Andrew Siffert is SVP and senior meteorologist at BMS