MARTIN'S COVE, Wyo. — An LDS filmmaker whose latest work will portray the tragedy of the 1856 Willie and Martin handcart companies said historians, writers and filmmakers who recount the past have a shared and sacred trust to ensure that their work accurately reflects the events that occurred.

Lee Groberg addressed members of the Mormon History Association on Sunday at the group's annual conference finale in the LDS Church's trek center near Martin's Cove. Scores of 19th century LDS emigrants in the Martin Handcart Company died in the cove in October 1856, weakened by hunger, exhaustion and exposure as they tried to find shelter from subzero temperatures.

Some of what occurred was re-enacted earlier this year as part of Groberg's latest documentary for PBS, "The Sweetwater Rescue," which was planned to coincide with the 150th anniversary of the handcart pioneers being celebrated this year by the church. He said the one-hour film will air nationwide, most likely in October, though a firm date has yet to be set.

His previous documentaries about segments in the early history of The Church of Jesus Christ of Latter-day Saints include "Trail of Hope," on the Mormon pioneer migration that began in 1847, and "American Prophet: The Story of Joseph Smith."

Groberg discussed specifics of filming his latest work, describing how film crews, extras and LDS missionaries near the cove tried to re-enact some of the events here as subzero temperatures and deep snow provided a realistic but challenging backdrop. "We prayed for snow and got it, but we didn't pray for 34 (degrees) below (zero) for several days."

At one spot on the Sweetwater River near the cove where the freezing pioneers are believed to have crossed, the ice was 8 to 10 inches thick, he said, so the film crew moved to another spot where the ice could be broken to allow the filming.

Because of the costs incurred with protracted waiting for perfect weather conditions, he settled for filming in a different spot. "In this case, it's a representation" of where the event occurred, he said.

Groberg noted he's highly sensitive to the importance of accuracy in his work, adding, "I'm not a studied historian." He thanked those in the audience who make history their life's work and strive to be as accurate as possible. "I appreciate the passion with which you tackle your craft."

He said the "scary part of that sacred trust" to be accurate is that both his film portrayals and the writings of schooled historians "become what people will look at" and believe is true, though the details of history tend to change over time as new sources of information come to light.

"Sometimes we don't get it right. Sometimes we publish the facts as we have them, then we learn to our horror that they have changed," he said.