With the potentially historic winter storm on its way, we started thinking about how much snow it would it take to collapse a roof and decided to do a bit of investigating. As we were researching other historic storms, we came across stories about the Knickerbocker Storm of 1922.
The Knickerbocker Storm was a blizzard that occurred on January 27–28, 1922 in the DC area. The storm took its name from the collapse of the roof of the Knickerbocker Theatre in Washington, D.C. on January 28 that killed 98 people and injured 133. The total recorded snow from that storm was between 28 (Downtown) to 33 inches (Rock Creek Park).
Since we didn’t have Dulles Airport back then, there were very few reports outside the city, but one could guess that it would have been more outside the city based upon what we know today about DC snowfall totals versus the surrounding area.
Should You Be Concerned?
According to FEMA and several online resources, most roofs in this area are built to withstand about 30 pounds per square foot (4 feet of powdered snow, 2 feet of heavy wet snow, or 6 inches of water). While this storm has the potential to drop up to 30 inches or more in some areas, most homeowners should have little to worry about.
The reason for this is because many homes today have sloped roofs and thus it is harder for them to accumulate the snow that you would encounter on a flat roof. Also, because they are designed to withstand “shadow” loads (or those caused by blowing snow that accumulates unevenly), they are generally stronger than those from the early 20th century. That said, it pays to be vigilant and to look for these “tell tale” signs of structural failure:
- Hard to Close Doors: If you notice that your doors upstairs in the house are harder to close, then this may be because the structural members of the house are taking more load than normal, and are sagging into the doorways.
- Cracks in Drywall: If you see cracks in your drywall in places not there before the storm, your roof may be failing.
- Water Damage: Water that is coming into your house from the roof area indicates the potential for a failure from either an overstressed structure, or from failing roof shingles.
What Can I Do?
First, in no situation should a homeowner attempt to climb on their roof to fix the problem. The storm we are about to experience will be historic with heavy winds and snow and you could be seriously injured or killed as a result of attempting to remove the snow.
Your first call should be to a local roofing company, and I have found one that will have someone to answer questions during the storm:
Loudoun Valley Roofing
37306 E Richardson Ln
Purcellville, VA 20132
In any case, if you see signs of your roof failing, call the Loudoun County Sheriff at 703-777-1021 to confirm if it is safe to evacuate your home. They can best advise whether rescue personnel can get to you, or if you would be able to get to someplace safe.
The Ian Bush Homes hopes that everyone stays safe during this dangerous storm and we will look forward to seeing you in the Spring or whenever this historic storm melts away!