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.
"You can look forward to doing it right: getting married, having a family, seeing your children and grandchildren, maybe even great-grandchildren," Packer said.
Rowe and her Rexburg, Idaho, publisher, Spring Creek Book Co., declined to be interviewed for this story.
However, Rowe later issued a statement, saying she agrees the curriculum for church classes "should only come from the sources recognized by the LDS Church as being authoritative."
"My story is not intended to be authoritative nor to create any church doctrine," she said. "It is simply part of my personal journey that I have chosen to share in hopes that it can help people to prepare for the times we live in by increasing their faith in Christ and by looking to our prophet and church leaders for guidance."
Apocalyptic views and fretting about the end times, of course, are nothing new.
In 1991, dozens of chapters of the conservative, mostly Mormon American Study Group sprouted across the Intermountain West, preaching a cataclysmic scenario, which included a global economic collapse, primarily in the banking industry, followed by rioting and natural disasters.
The group, which was based in part on teachings of the late, ultraconservative LDS prophet Ezra Taft Benson, had more than 5,000 participants in 35 to 40 chapters.
Next week, the Ezra Taft Benson Society will host a banquet for members in Orem, under the title "Exposing and Stopping Modern Gadianton Robbers."
Apocalyptic beliefs are hardly unique to Mormons.
"Any messianic religion has built-in expectations that the Messiah will return," says Patrick Mason, Howard W. Hunter chair of Mormon studies at Claremont Graduate University in Southern California, "and that God will make right everything that's wrong."
That belief, Mason says, is "deep in the DNA of religious people who look at the world and sense that they're not winning and that their side isn't in power."
It was shared by early Christians who were being thrown to lions, by medieval Christians being wiped out by the plague, says Mason, and by 19th-century Mormons being driven from state to state.
Today's Christian conservatives might worry about financial uncertainty, he says, about President Barack Obama, or about feeling their rights are being obliterated.
As for the blood moon, Mason says, "people have been looking to the sky for signs ever since Jesus said to."
Believers are warned to be on the lookout always, he says. "But if the end times come with the kinds of disasters and calamities scripture describes, food storage ain't gonna save you."