Hail Size Chart: Understanding Roof Damage
Published 2026-07-23 · Updated 2026-07-23
Understanding hail size charts is crucial for property owners to assess potential roof damage. Learn how to read hail size charts and take preventive measures to protect your roof.
Introduction to Hail Size Charts
Hail size charts are essential tools for property owners, contractors, adjusters, and attorneys to assess the potential damage caused by hail storms. A hail size chart is a graphical representation of the different sizes of hailstones, which helps to determine the extent of roof damage. In this article, we will explore how to read a hail size chart, what each size really means for your roof, and provide practical guidance on prevention and mitigation.
What is a Hail Size Chart?
A hail size chart is a chart that compares the size of hailstones to familiar objects, such as coins or balls. The chart is used to estimate the size of hailstones that have fallen in a particular area. The National Weather Service (NWS) uses a hail size chart to categorize hailstones into different sizes, ranging from pea-sized (0.25 inches) to softball-sized (4.00 inches).
How to Read a Hail Size Chart
Reading a hail size chart is relatively straightforward. The chart typically includes a series of columns or rows with different objects, such as coins or balls, and the corresponding hail size in inches. To read the chart, simply match the size of the hailstone to the corresponding object. For example, if the hailstone is the size of a quarter (1.00 inch), it is considered severe hail and can cause significant damage to roofs.
What Each Hail Size Means for Your Roof
The size of the hailstone has a significant impact on the type and extent of roof damage. According to the StormAuditor KNOWLEDGE BASE, asphalt shingles typically begin showing functional hail damage around 1.00–1.25 inches impacts. Metal roofs dent cosmetically at ~1.00+ inches but rarely fail functionally until 1.75+ inches. Window/skylight breakage becomes common at ~1.75+ inches.
Practical Guidance for Property Owners and Contractors
Property owners and contractors can take several steps to prevent and mitigate hail damage to roofs. These include:
- Regularly inspecting roofs for damage and wear
- Installing impact-resistant roofing materials, such as UL 2218 Class 4 shingles
- Trimming trees and shrubs to reduce the risk of branch damage
- Installing gutter guards to prevent clogs and damage
Limitations of Hail Size Charts
While hail size charts are useful tools for assessing potential roof damage, they have some limitations. For example, the size of the hailstone is not the only factor that determines the extent of damage. Other factors, such as the velocity and angle of the hailstone, can also impact the severity of the damage. Additionally, hail size charts may not account for the type and condition of the roof, which can also affect the extent of the damage.
Related StormAuditor Tools
To learn more about hail size charts and roof damage, visit the following StormAuditor tools:
- Hail Explorer to view state-wide MESH swaths and reports
- Address Lookup to view property-level historical weather reports
- Methodology to learn more about StormAuditor's hail estimation methodology
FAQ
Q: What size hail can cause roof damage?
A: According to the StormAuditor KNOWLEDGE BASE, asphalt shingles typically begin showing functional hail damage around 1.00–1.25 inches impacts.
Q: How do I read a hail size chart?
A: To read a hail size chart, simply match the size of the hailstone to the corresponding object on the chart.
Q: What is the difference between functional and cosmetic damage to a metal roof?
A: Functional damage to a metal roof occurs when the roof is no longer able to perform its intended function, such as keeping water out. Cosmetic damage, on the other hand, refers to damage that affects the appearance of the roof, such as dents or scratches.
Q: Can StormAuditor provide a hail size chart for my area?
A: Yes, StormAuditor provides hail size charts and reports for specific areas. Visit the Hail Explorer tool to view state-wide MESH swaths and reports.
Q: How can I prevent hail damage to my roof?
A: Property owners can take several steps to prevent and mitigate hail damage to roofs, including regularly inspecting roofs, installing impact-resistant roofing materials, and trimming trees and shrubs.
Q: What is the relationship between hail size and wind speed?
A: According to the StormAuditor KNOWLEDGE BASE, wind speed can also impact the severity of hail damage. However, the exact relationship between hail size and wind speed is complex and depends on various factors, including the type and condition of the roof.