Before I begin I'd like to restate from the other answer that the phrase "Great Tribulation" is not used in Mormon terminology/teachings and LDS teachings most closely align with post-tribulationist. That is Mormon's believe in a chronology that is along the lines of tribulation, second coming, Millenium, and then the last judgement. I will not go into great detail as most of this is covered in LDS manuals and covers several chapters, feel free to look at the referenced manuals if you want more detail.
- What physical events do Mormons believe will happen before or during the Great Tribulation?
Signs of the Second coming1
- Wickedness, War, and Turmoil-being fulfilled
- The Restoration of the Gospel-fulfilled
- The Coming Forth of the Book of Mormon-fulfilled
- The Gospel Preached to All the World-partly being fulfilled
- The Coming of Elijah-fulfilled
- Lehi's Descendants Will Become a Great People-partly being fulfilled
- Building of the New Jerusalem
- Other signs (see the scripture references at the bottom of the chapter if you want the others)
- Jesus will cleanse the earth-wicked will be destroyed
- He will judge His people
- He will usher in the Millenium
- He will complete the First Resurrection
- He will take His rightful place as King of heaven and earth
- Temple/Missionary work
- Satan bound
- Peace on earth
- Righteous government
- No death
- All things revealed
- A final struggle at the end of Millenium when Satan will be set free for a short time. Satan will gather his armies and they will be cast out forever.
- Judged by words, works, and thoughts
- Judged by records
- Inheriting a place in a Kingdom of Glory
- 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"?
Because this isn't Mormon terminology it is hard to get a specific answer but based on the previous answer (above) there are spiritual and physical reasons that would warrant the label "Great Tribulation".
- Do Mormons have any official beliefs on how long the Great Tribulation is expected to last?
No. We have to measure when the first sign of the Jesus' Second Coming is to the Second coming (no specific time period), plus 1,000 year Millenium, and then Final Judgement (again no specific time period). So at least 1,000 years.