By D.W.G. Kalani Tharanga, JadeTimes News
Both tornadoes and hail are formidable weather phenomena in the United States, each with its unique capacity for destruction. Comparing their impacts reveals crucial insights for better preparing and mitigating the effects of such extreme weather events.
Tornadoes dominate the American consciousness when it comes to weather related risks. With an annual average of about 1,200 tornadoes, their potential for catastrophic damage is well recognized. Tornadoes that strike urban areas can be particularly lethal, as evidenced by the 2011 outbreak that claimed over 300 lives in a single day. Despite this, factors like gender, optimism bias, and experiences with weaker tornadoes can lead to underestimating their threat.
The Underestimated Threat of Hail
While tornadoes capture much of the public's attention, hail poses a significant and often underappreciated threat. In 2023, heatwaves claimed more lives than tornadoes, and hail accounts for 60 to 80% of insured losses from severe thunderstorms annually, according to the US catastrophe modelling industry. Extreme winds, including tornadoes, account for up to a third, with lightning covering the remainder.
For those who have experienced only mild hail, it may seem relatively harmless. However, hail can be extraordinarily destructive. For example, in June, a flight from Spain to Austria suffered severe damage from a hailstorm. In 2018, a Colorado zoo experienced softball sized hail that killed two birds and injured 14 people. Although fatalities from hail are rare, there have been eight recorded deaths over the past 70 years.
Harold Brooks, a senior research scientist at the US National Oceanic and Atmospheric Administration, witnessed firsthand the havoc hail can wreak when a 2021 hailstorm caused extensive property damage in Norman, Oklahoma. Brooks noted that while tornadoes can cause more extreme damage, hail is a more frequent threat. Vittorio Gensini, a meteorology and climatology professor at Northern Illinois University, pointed out that hailstorms are more widespread and frequent than tornadoes, often spanning several kilometers and lasting for hours.
Hailstorms, A Growing Challenge for the Insurance Industry
Hailstorms pose a particular challenge for the insurance industry. According to Ian Giammanco, a meteorologist at the Insurance Institute for Business and Home Safety, about 10% of hail producing thunderstorms cause significant damage, leading to over $10 billion in insured losses annually since 2008. Even relatively small hailstones can inflict substantial damage, hail as small as 1 inch in diameter can damage vegetation, while stones 2 inches and larger can crack windshields and break through roofs.
Despite the significant threat from hailstorms, tornadoes still represent a more immediate danger to life. "Hail will cause more insured losses," Gensini notes, "but a tornado is more likely to cost lives."
Both hail and tornadoes often arise from the same severe thunderstorms, known as supercells. As climate change intensifies, conditions for larger hailstones become more favorable due to stronger storm updrafts, although higher temperatures also cause smaller hailstones to melt before reaching the ground. Brooks and Gensini agree that the variability in tornado activity is expected to increase with climate change, due to rising temperatures and humidity in the lower atmosphere and changes in vertical wind shear.
Advancing Hail Research and Resilient Infrastructure
Despite the threats posed by hailstorms, much remains unknown about their dynamics. To address this, Gensini and his colleagues have initiated the ICECHIP project, a field campaign using advanced measurement tools to study hail producing conditions. This research aims to improve forecasting models and enhance predictions of hail impacts.
New materials, such as rubber plastic shingles, are being developed to withstand hail damage. However, current building codes do not require hail resistance, a gap that Giammanco hopes will soon receive more attention. While tornado resistant design requirements exist for critical facilities like hospitals and schools, expanding these standards to other types of construction remains a topic of discussion.
Giammanco's personal experience underscores the urgency of these considerations. Recently, a supercell storm produced a tornado that passed within half a mile of his home, highlighting the ever present danger of these powerful weather events.