Saturday, February 16, 2013
Who knew that on February 15, 2013, I'd need to write about preparing for and responding to the threat of meteorites? Although scientists and sky watchers had been talking about a 150-foot diameter asteroid, 2012 DA14, that was predicted to come within 17,000 miles of the earth, everyone was completely taken by surprise by a 50-foot diameter meteorite that came down over the city of Chelyabinsk in the Ural mountains of Russia, 15 hours earlier. The two were not related, based on timing and direction.
Asteroids are small rocky objects that orbit the sun. When they enter the atmosphere, they are called meteors, although most that we see as "shooting stars" are about the size of a grain of sand. When a meteor enters the atmosphere at hypersonic speeds, it not only creates a sonic boom shockwave, it heats up so quickly that it may disintegrate with something like an explosion. The resulting shockwave can damage buildings and break glass windows. About 1000 Russians were injured by flying glass.
While we see shooting stars every day, an event as large as February 15ths happens maybe every five years or so. Mostly they happen over water or remote areas and are unreported. The largest previously reported meteor blast leveled hundreds of square miles of forest over Tunguska in Siberia in 1908.
Meteor strikes like Friday's are almost completely unpredictable. While we have the technology to locate, identify and track small--like Friday's meteor--objects, we just don't have the resources. So unless someone is looking in just the right place at just the right time (like they were when they discovered the asteroid 2012 DA14), we won't know when the next one will hit. But from Chelyabinsk's experience, we know that the main damage is window breakage. While that seems minor enough, having no windows in the middle of a Siberian winter can create an exposure danger as nighttime temperatures plunge well below freezing.
Preparations include having a family plan for communicating and reuniting with each other in case chaos and damage is more widespread than in Friday's event. It is also important to have a 72-hour kit that you can grab if you need to leave an uninhabitable residence. One lesson learned that also applies to severe storms, strong winds or hailstorms is to have some materials and supplies on hand to cover several broken windows until you can have them replaced. For example, some heavy poly sheeting and duct tape could be used to cover windows, although for large openings, some kind of a backing frame like wooden crosspieces or lattice might be needed for support. If you are a homeowner, it would be prudent to keep an extra sheet of plywood or two on hand, that could be cut to shape. Don't forget to figure out how you would attach the plywood, and store grabber screws or lag screws, as well.