On February 10 at approximately 1656 GMT, the Iridium 33 and Cosmos 2251 communications satellites collided over northern Siberia. The impact between the Iridium Satellite LLC-owned satellite and the 16-year-old satellite launched by the Russian government occurred at a closing speed of well over 15,000 mph at approximately 490 miles above the face of the Earth. The low-earth orbit (LEO) location of the collision contains many other active satellites that could be at risk from the resulting orbital debris.
The following videos, interactive 3D Viewer files, 3D models, and high-resolution images are available to better understand this event.
I don't understand how this could happen.