Coronal Mass Ejection

Solar activity occurs at regular intervals (11 years), Earth's Sun has just started a new cycle and around 2012 the activity will be at its peak. This, of course, increases the probability of this threat. Ejections that are large enough to cause a threat to Earth are probably frequent enough, but they still need to 'hit' the Earth. The last time this happened was some time ago, though it did disrupt power grids and set fires. If this happened today, Earth would loose all of its satellites, probably the space station as well. Not that they would burn up, but rather just stop working. Surface level communications, power distribution would also be taken out causing a good deal of chaos. There may also be fires, perhaps fire storms occurring, and without communications these could be devastating.