Each spring, particularly across the central and southeastern United States, a volatile mix of warm, moist air and cold, dry systems can quickly escalate into violent tornadoes, damaging hailstorms, and dangerous flooding. For insurers, these seasonal weather patterns are major drivers of climate and catastrophe losses in the first half of the year.
Many of these hazards, particularly tornadoes, hail, damaging winds, and severe thunderstorms, are grouped into a broader insurance category known as severe convective storms (SCS). These events often produce multiple destructive hazards at once, triggering widespread property damage across large geographic areas.
Events once classified as “secondary perils,” including hail, wind, and tornadoes, are increasingly driving insured losses as primary drivers. Severe convective storms alone now generate tens of billions in damages annually and, in many years, rival or exceed losses from traditional primary perils such as hurricanes.
Guidewire HazardHub notes that these seasonal perils account for a growing share of property damage and insured losses nationwide. As development expands into weather-exposed regions and risk patterns shift across coastal, wildfire-prone, and tornado-affected areas, understanding hazard geography and financial impacts is becoming increasingly important for insurers, homeowners, and policymakers.
Below are some of the most significant spring weather threats shaping risk across the United States.
Tornadoes: The Most Destructive Spring Threat
Spring marks the peak season for U.S. tornado activity, including the most violent events, which can cause catastrophic damage to homes, businesses, and infrastructure within minutes.
According to the HazardHub Tornado Risk Score, approximately 4.57 million housing units in the U.S., or about 3.4% of all homes, are located in areas classified as high or very high tornado risk.
NOAA data analyzed by HazardHub show about 1,558 tornadoes in the United States in 2025, a still-elevated total though lower than the record-setting 1,796 tornadoes recorded in 2024, which was one of the most active years on record. The long-term U.S. average is roughly 1,200–1,300 tornadoes annually, highlighting how elevated tornado activity has remained in recent years.
Over the past 15 years, April to June have been the most active tornado months, with the highest number and severity of storms.
HazardHub's analysis of NOAA data shows a clear seasonal pattern in U.S. tornado activity. Events rise from 35–48 in January, and 49–60 in February. Activity peaks around 320 in May, then gradually declines through summer and fall.
- March: ~128 tornadoes per year on average
- April: ~253 tornadoes per year on average
- May: ~320 tornadoes per year on average (peak month)
The United States has more tornadoes and violent tornadoes than any other country. While Tornado Alley (northern Texas, Oklahoma, and Kansas) once saw the most tornado activity, research now shows a shift east. More tornadoes are occurring across the Southeast and Ohio Valley—sometimes called "Dixie Alley"—putting denser eastern regions at increased risk.
Recent data show that tornado activity remains highly concentrated across the central and southeastern United States. In 2025, Texas recorded the highest number of tornadoes with 162 reports, followed by Illinois (146), Missouri (120), Mississippi (111), and Alabama (72), tied with North Dakota for fifth place) highlighting how severe weather outbreaks can shift year to year while remaining concentrated across the broader Tornado Alley and Mid-South regions.
The destructive power of tornadoes can lead to severe damage to infrastructure and long-term disruption to communities. Recent outbreaks illustrate the scale of these losses. A single tornado outbreak in March 2025 caused an estimated $11 billion in damage, making it one of the costliest tornado events in U.S. history.
Severe Convective Storms and Hail: Driving Billions in Damages
While tornadoes draw headlines, hail typically accounts for the largest share of insurance claims from severe convective storms. Hailstorms can cause widespread roof, siding, and vehicle damage, leading to thousands of claims after a single event. For insurers, hail remains a top source of weather-related losses.
Severe convective storms generated about $50 billion in global insured losses in 2025, according to the Swiss Re Institute. Hail was the primary driver of these losses, with U.S. claims accounting for the bulk of the totals.
HazardHub’s Enhanced Hail Risk Score reveals that 93% of U.S. housing units face some hail risk, with about 5% located in high-risk zones, mainly in the central and southern regions.
Despite a few high-risk zones, hail's financial toll remains significant. The Insurance Information Institute reports that wind and hail account for roughly one-third to 40% of homeowners' claims, with hail as a major driver.
Flooding: America’s Most Costly Climate Risk
Flooding is another major spring weather hazard and remains the most costly natural disaster in the United States in terms of total economic impact. Most of the financial burden is not covered by private property and casualty insurers. Instead, flood losses are largely absorbed through the National Flood Insurance Program (NFIP) and federal disaster relief. As a result, private insurers typically assume only a limited share of total flood risk.
Flood risk is driven by a combination of factors, including intense rainfall, rapid snowmelt, and overflowing rivers—events that can inundate communities, damage infrastructure, and disrupt local economies.
According to FEMA and the U.S. Senate Joint Economic Committee, flooding plays a role in the overwhelming majority of natural disasters across the country:
- 90% of all natural disasters involve flooding
- 75% of presidential disaster declarations are flood-related
Despite this prevalence, insurance coverage remains limited. Only about 4% of U.S. homeowners carry flood insurance, leaving a significant protection gap.
When flood losses go uninsured, the impact extends well beyond individual households. The economic effects ripple through entire communities—slowing recovery, disrupting businesses, and shifting much of the financial burden to federal disaster relief programs and, ultimately, taxpayers.
FEMA claims data also highlights clear geographic patterns in flood risk. Texas, Louisiana, and California face the greatest exposure to riverine flooding, while coastal risks are highest in states such as New Jersey, New York, and Virginia. When measured by total flood losses, Texas, New Jersey, and Louisiana consistently rank among the highest-impact states.
As flood risk intensifies and coverage gaps persist, insurers face growing pressure to better understand, quantify, and manage flood exposure—making high-resolution data and forward-looking risk insights increasingly critical.
Insight into a More Volatile Storm Season
Spring storms have always been a defining feature of the U.S. climate. But as development expands into weather-exposed regions and severe convective storms generate increasingly costly losses, the financial stakes for insurers continue to grow. Tornadoes, hailstorms, and flooding are no longer isolated events. They are recurring drivers of catastrophe losses that can affect entire insurance portfolios across multiple states.
In this environment, high-resolution risk data is becoming essential for insurers seeking to better understand and manage weather exposure. Platforms such as Guidewire HazardHub provide property-level insights into dozens of natural hazards, helping insurers evaluate tornado, hail, flood, and wind risks before policies are written.
By integrating this type of geospatial risk intelligence into underwriting and portfolio management, insurers can improve risk selection, strengthen pricing accuracy, and enhance portfolio visibility. Its impact becomes even more powerful when paired with mitigation strategies—enabling insurers not only to assess risk, but to encourage actions that reduce it, such as adopting fortified, hail-resistant roofing or other property-level resilience measures.
This shift is already being recognized across the industry, as climate risk, insurance pricing, and long-term exposure become increasingly interconnected. Recent coverage in the Financial Times’ P&C Specialist highlights how AI is reshaping the role of service providers, elevating data as a competitive differentiator and reinforcing the value of ecosystem partnerships and intelligent core platforms in the future of insurance.
Look for our Hurricane and Wildfire season reports as those seasons approach in June.