On August 6, 2013 the Twin Cities experienced a destructive supercell thunderstorm event that produced 1”-2” hailstones and high wind damage throughout the region, tracking along I-94 from south of Fargo to Eau Claire. Power was lost and vehicles were damaged throughout Eden Prairie, Edina, St. Louis Park, and Bloomington. Thankfully, although the storm’s rotating nature caused the National Weather Service to issue several tornado warnings, no tornadoes were reported. Among the result of that hail storm were roofs of houses, businesses, apartments, garages and more, that took a real beating. We expect these roofs to cover us, to protect us from the storms of life, but a hail storm like this one takes a toll on these roofs.
Hail’s impact on your home, or anything else outside, is affected by the size, density, and velocity of the hail stone. Hail can be smaller than a pea or larger than a softball, but size isn’t the only factor in assessing how much damage it causes when it hits your roof.
Hail is formed when rain droplets go through a series of updrafts. Each time the droplet rises and falls another layer of ice is added. In cold-weather storms the hail created tends to be relatively soft and small, with a density of 0.5 to 0.7 grams per cubic centimeter. Warm weather storms, like the one we experienced August 6th, produce larger, denser hailstones that near the density of ice (0.9 grams per cubic centimeter).
Velocity is a Factor
While typically you would expect a bigger hailstone to fall faster and hit harder, wind direction can factor into hail’s velocity. The direction of the wind can speed up or slow down the velocity of a hailstone. The result of that velocity change will factor into the amount of force that the hail hits your roof and any damage that occurs.
What Does Hail Damage Look Like?
You might expect large dents or even puncture marks to appear on your roofing materials when hail storms hit your roof. While these types of catastrophic failures do occur and are easy to spot, there are other types of damage that are not quite as easy to identify. Slight dimpling of asphalt shingles also indicate damage. Metals used in vents or as flashing will also show signs of hail impact and can help in the assessment of damage.
The age and materials used for the roofing surface are factors that must be taken into account when inspecting for hail damage. Older shingles as well as thinner, lower grade shingles are more likely to have low hail resistance. As the shingles age the materials used can become hard and brittle. Getting hit with hail will cause granule loss, and can fracture the matting at the core of the shingle. Without appearing dented, these shingle could still fail, over time allowing rain through your roof’s surface.
While the Storm is Raging
If possible taking notes while the hail is falling can go a long way in helping provide information about the severity of the storm. Details about how long the hail fell, the size of the hail, and the direction the wind/hail came from. If you have an opportunity, taking a picture of some of the hail stones using a ruler or coin as a point of reference for size is also a good idea.
What to Look for After Hail Hits
After a storm rolls through your area, if you have a shingle roof, look for the mineral granules that may have washed off your roof before you climb up on the roof. Also look around your neighborhood. Have there been dents added to any cars or plants damaged? These can also be indicators of how bad the damage.
Once on the Roof
If you do climb the ladder to check your roof, the first thing you will be looking for are granules that have not yet washed down your guttering. Also look to see where those granules have come off the shingles. Areas that show granule loss will have an exposed “fresh” looking shingle substrate where that area has not yet been weathered by the sun. Larger hailstones can produce a dents or visible damage points in shingle roofs’ surfaces. Signs of hail damage can be as subtle as a small dimple in a few shingles. If you suspect damage it is best to have your roof checked by reputable roofing professionals.
When hail storms pummel roofs in Eden Prairie, Bloomington, St. Louis Park, or Edina, contact the roofing professionals at Midwest Exteriors Plus! We have the experience you need when going through the hail storm recovery process and know what the insurance companies expect. Your quality roofing and exteriors company, serving the Twin Cities for over 40 years.