Storms no more likely to stall over land than in the past: TigerRisk

Storms are no more likely to stall over land than they were 150 years ago, according to TigerRisk, a reinsurance broker, advisor and catastrophe analytics firm.

Insurers have become increasingly concerned about stalling storms in recent months, after 2017 and 2018 saw back-to-back hurricanes stalling once crossing the coast. This has led to questions over whether global warming or other forces are making such a phenomenon more likely than in the past.

Storms that stall over land have cost insurers billions. Instead of slamming into shore, barreling inland and then losing strength, Hurricane Harvey in 2017 and Hurricane Florence in 2018 came ashore and then stalled, dumping huge amounts of rainfall over the coastal plains.

Harvey was the second costliest hurricane in US history after Katrina in 2005, resulting in losses of $125 billion, of which $19 billion were insured. Florence, which stalled over North Carolina, caused losses of $45 billion of which only $4.6 billion were insured.

But research byTigerRisk has found that the frequency of stalled storms has remained relatively constant since 1851. The company’s analytics team conducted an extensive review of weather data over that period, including thousands of storms, and found 37 tropical storms that had stalled once they had come ashore. “Only in six cases did they occur back-to-back in consecutive years,” noted Anna Neely, research and development analyst at TigerRisk.

However, more research is warranted on what causes storms to stall and the unique way in which these storms cause damage, said TigerRisk.

Moreover, even if storms continue to stall at the normal rate, the increasing dollar amount of damage caused points to the inadequacy of flood control and insufficient flood insurance, it added.