Early this morning (Wednesday, January 27th, 2016), a vast number of iOS and Mac users found their Safari browsers crashing on their iPhones, iPads and Macs. Although the reason was not determined, a quick temporary fix was found by online forum members. You simply needed to go into Settings and toggle off Safari Suggestions.
At the time of this post, Apple has yet to release an official statement on the crashing, but the issue seems to have mysteriously vanished, even for those who haven't used the temp fix. This suggests that Apple quickly moved on the issue and nailed it down.
If you happen to see any further details on the problem that we might have missed in this report, feel free to share it in this thread.