What kind of characteristics does the Great Tribulation have in LDS eschatology?

There is this other question with an answer that touches on the Great Tribulation as it is viewed in LDS eschatology, but I would like to ask more specifically about the situation on earth during the Great Tribulation: 1. What physical events do Mormons believe will happen before or during the Great Tribulation? 2. In what sense will it be a "Great Tribulation" - is this mostly symbolic or are there spiritual or physical (e.g. economical) reasons that warrant the label "Great Tribulation"? 3. Do Mormons have any official beliefs on how long the Great Tribulation is expected to last?