Jordan Jensen, a salesman at Emergency Essentials, said his Bountiful store has been "crazy busy, sales up by definitely a large amount."
Those 72-hour emergency kits are "almost impossible to keep on the shelves," Jensen says, "and we get a shipment every day."
A lot of customers, he says, believe "this is the month it will all happen — with a 'blood moon' and a currency collapse and everything."
MORE: Watch our Trib Talk video chat with two Mormon scholars about the preppers and their fears about the end times.
Here's how the doomsday scenario plays out: History, some preppers believe, is divided into seven-year periods — like the Hebrew notion of "shemitah" or Sabbath. In 2008, seven years after 9/11, the stock market crashed, a harbinger of a devastating recession. It's been seven years since then, and Wall Street has fluctuated wildly in recent weeks in the wake of China devaluing its currency.
Thus, they believe, starting Sept. 13, the beginning of the Jewish High Holy Days, there will be another, even larger financial crisis, based on the United States' "wickedness." That would launch the "days of tribulation" — as described in the Bible.
They say Sept. 28 will see a full, red or "blood moon" and a major earthquake in or near Utah. Some anticipate an invasion by U.N. troops, technological disruptions and decline, chaos and hysteria.
Some of these speculations stem from Julie Rowe's books, "A Greater Tomorrow: My Journey Beyond the Veil" and "The Time Is Now."
Rowe, a Mormon mother of three, published the books in 2014 to detail a "near-death experience" in 2004, when the author says she visited the afterlife and was shown visions of the past and future.
Though Rowe rarely gives specific dates for predicted events, she did describe in a Fox News Radio interview "cities of light," including scores of white tents where people will live in the mountains and sometimes be fed heavenly "manna." She saw a "bomb from Libya landing in Israel, but Iran will take credit."
And "Gadianton robbers" of Book of Mormon infamy, meaning secret and corrupt leaders, are "already here."
Her purpose in speaking out, Rowe told interviewer Kate Dalley, was "to wake more of us up. ... We need each other as we unify in righteousness and continue to build a righteous army. When we need to defend the [U.S.] Constitution, we will be ready."
For the past year, the popular writer has been sharing her experience and visions at Mormon venues nationwide, drawing crowds of eager — and worried — listeners. Her two books have sold more than 20,000 copies apiece.
In a rare move, officials with The Church of Jesus Christ of Latter-day Saints sent a memo to administrators and teachers in the Church Educational System, saying, "Although Sister Rowe is an active member of the [LDS Church], her book is not endorsed by the church and should not be recommended to students or used as a resource in teaching them. The experiences ... do not necessarily reflect church doctrine, or they may distort doctrine."
The late Mormon apostle Boyd K. Packer said in the October 2011 LDS General Conference that the "end" was not near and urged young Latter-day Saints to plan to live long, productive lives.