The article doesn't mention the other 'why', which is 'why are there so many people combing Antarctica for 'meteorites' at all? The answer is that China has sent dozens of 'meteorite hunting' expeditions to Antarctica over the years. In other news, Antarctica also has large fossil fuel and mineral reserves, but - no - it's definitely the space fragments they're looking for...

Something - anything - disappating that amount of energy that quickly, is going to make a big bang, even if it doesn't leave a huge crater. The Tunguska Event didn't leave a crater, but it would have 'broken a few windows' if it had occurred near a built-up area. If by 'minimal threat to life' you mean 'all life on Earth', then - absolutely - this would have been a local disaster - a few hundred square miles.