As hail season is in full swing in much of the country, here are a few facts:
- Hail causes about $1 billion dollars in damage to property and crops each year.
- Hail forms when updrafts in thunderstorms lift raindrops into extremely cold areas of the atmosphere where they freeze into balls of ice when they come into contact with ice crystals, dust or some other bit of material. They grow by colliding and freezing with supercooled water drops and continue to grow until the storm’s updraft can no longer support the weight of the ice. Then they fall to earth. The stronger the updraft, the larger the hailstone can grow.
- Any thunderstorm can produce hail, but large hail is most common in “supercell” thunderstorms. Interestingly, most supercells produce hail, while fewer than 30% of supercells produce tornadoes.
- The largest hailstone ever recorded in the U.S. fell on July 23, 2010, in Vivian, South Dakota. It was eight inches in diameter and weighed almost two pounds.
Because it faces the sky, the most vulnerable area of any building is the roof. If your building is located in the midwest or south, hail is likely to fall on it at some point and when it does, there is potential for damage. Even a relatively minor hail storm can compromise the watertight integrity of your flat roofing system.
A quick visual inspection can show noticeable cracks, indentations or punctures to the membrane. But even less-obvious fractures can lead to roof leakage and failure down the road. In fact, problems may not show up for months or even years after the hail event. Even if leaks don’t appear, the impact of hail can weaken the roofing membrane (shortening its life expectancy) and damage underlying insulation. Dented insulation or a separation of the insulation’s facer from its interior section can cause the roof membrane above it to become unsupported, which decreases its strength and ability to resist further cracking and problems.
If your building has experienced hail, it would be a good idea to examine it for any signs of trouble. If your roof is obviously damaged, leaking, or so old that it might not survive another storm, please give us a call!